Polarizing plate and display using the same

ABSTRACT

A polarizing plate comprising a polarizing film having thereon a retardation film containing a plasticizer and a cellulose ester, wherein a free volume radius of the retardation film determined by positron annihilation lifetime spectroscopy is in the range of 0.250-0.310 nm.

This application is based on Japanese Patent Application No. 2004-345733filed on Nov. 30, 2004 in Japanese Patent Office, the entire content ofwhich is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a polarizing plate and a display usingthe same, and specifically, relates to a polarizing plate having smallvariation in retardation values due to change in production conditions,and to a display using the same.

BACKGROUND OF THE INVENTION

A large sized liquid crystal display (LCD) has recently attractedattention. With respect to large-sized LCDs, required therein is higherperformance, for example, in viewing angle, contrast and stability inquality against environmental changes, compared to the requiredperformance for conventional personal notebook computers or LCDmonitors. Therefore, higher performance is also required for thepolarizing plates used for the large sized LCD device or for thecellulose ester film used for the polarizing plate. Variations inretardation values have been observed in polarizing plates havingthereon a retardation film, due to planned or unplanned changes inproduction conditions. Improvement for this problem has been desiredspecifically for large sized polarizing plates. Further, in order toimprove the display performance of an LCD, a backlight unit has morecommonly been provided behind the liquid crystal cell to directlyilluminate the liquid crystal cell without usin a light guide. However,in this direct illumination backlight system, when a LED backlight unitis used instead of a fluorescence tube backlight unit, variations indisplay quality tends to increase in accordance with the temperatureincrease caused by heat generated from the LED backlight unit, andfurther improvement specifically for obtaining displays exhibitinguniform contrast has been desired.

In order to obtain a display exhibiting long term stability of displayquality and high productivity, disclosed is a retardation film of whichmoisture permeability is reduced (for, example, refer to Patent Document1). Also, in order to obtain a display exhibiting limited light leakagecaused by thermal distortion and high display quality, disclosed is aretardation film of which expansion coefficient due to moistureabsorption is suppressed below a prescribed value (for example, refer toPatent Document 2). A polarizing plate exhibiting high durability evenunder a high humidity-high temperature condition is also disclosed,which is attained by controlling the diffusion coefficient of boric acidin the polarizing plate (for example, refer to Patent Document 3).However, these improvements have not been fully satisfactory. In PatentDocument 3, disclosed is a method to control the diffusion coefficientof boric acid by decreasing free volume in a cellulose acylate film, andin paragraph [0015] of this patent document, it is described that thefree volume in a cellulose acylate film can be decreased by increasingthe amount of crystals in the film. However, variations of retardationvalues of polarizing plates due to changes in producing conditions havenot been fully reduced so far. Specifically, in an amorphous-likecellulose ester, for example, a mixed acid ester of cellulose such ascellulose acetate propionate, a notable effect has not been fullyobtained.

Patent Document 1: Japanese Patent Publication Open to Public Inspection(hereafter referred to as JP-A) No. 2002-14230

Patent Document 2: JP-A No. 2002-71955

Patent document 3: JP-A No. 2004-279931

SUMMARY OF THE INVENTION

An object of the present invention is to provide a polarizing platehaving on one surface of which a retardation film, the polarizing plateexhibiting reduced variation in retardation values due to changes inproduction conditions and to provide a display exhibiting uniformdisplay quality. One of the aspects of the present invention to achievethe above object is a polarizing plate comprising a polarizing filmhaving thereon a retardation film containing a plasticizer and acellulose ester, wherein a free volume radius of the retardation filmdetermined by positron annihilation lifetime spectroscopy is in therange of 0.250-0.310 nm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram explaining the stretching angle in a stretchingprocess.

FIG. 2 is the schematic view showing a typical example of a tenterprocess used in the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The above object of the present invention is attained by the followingstructures.

(1) A polarizing plate comprising a polarizing film having thereon aretardation film containing a plasticizer and a cellulose ester, wherein

a free volume radius of the retardation film determined by positronannihilation lifetime spectroscopy is in the range of 0.250-0.310 nm.

(2) The polarizing plate of Item (1), wherein

a free volume parameter of the retardation film is in the range of1.0-2.0.

(3) The polarizing plate of Item (1) or Item (2), wherein

the cellulose ester is an ester of mixed aliphatic carboxylic acids eachhaving 2-22 carbon atoms.

(4) The polarizing plate of any one of Items (1) to (3), wherein

Ro and Rt defined by the following formulas satisfy the followingconditions:

Ro is in the range of 30-300 nm; and

Rt is in the range of 70-400 nm,

-   -   wherein        Ro=(nx−ny)×d        Rt=(((nx+ny)/2)−nz)×d    -   wherein RO represents an in-plane retardation value; Rt        represents an out-of-plane retardation value in a thickness        direction; nx represents an in-plane refractive index in a slow        axis direction; ny represents an in-plane refractive index in a        fast axis direction; nz represents an out-of-plane refractive        index in the thickness direction; and d represents a thickness        (nm) of the retardation film.        (5) A display comprising a liquid crystal cell, a direct        illumination backlight unit and the polarizing plate of any one        of Items (1) to (4).

The present invention provides a polarizing plate having on one surfaceof which a retardation film, the polarizing plate exhibiting reducedvariation in retardation values due to changes in production conditionsand provides a display exhibiting uniform display quality.

The preferred embodiments of the present invention will now be detailed,however, the present invention is not limited thereto.

The characteristics of the structures of the present invention are asfollows.

(6) A stretched cellulose ester film containing a plasticizer and acellulose ester and having a free volume radius determined by positronannihilation lifetime spectroscopy in the range of 0.250-0.310 nm.

(7) The stretched cellulose ester film of Item (6) having a free volumeparameter determined by positron annihilation lifetime spectroscopy inthe range of 1.0-2.0.

(8) The stretched cellulose ester film of Item (6) or Item (7), whereinthe cellulose ester is an ester of mixed carboxylic acids having 2-22carbon atoms.

(9) The stretched cellulose ester film of any one of Items (6) to (8),wherein the cellulose ester is cellulose acetate propionate or celluloseacetate butyrate.

(10) The stretched cellulose ester film of any one of Items (6) to (9),wherein Ro is in the range of 30-300 nm and Rt is in the range of 70-400nm.

(11) The stretched cellulose ester film of any one of Items (6) to (10),wherein a dimensional variation of the cellulose ester film after it isstored under a condition of 80° C. and 90% RH is within ±2%.

(12) A polarizing plate having thereon a retardation film containing aplasticizer and a cellulose ester, wherein

a free volume radius of the retardation film determined by positronannihilation lifetime spectroscopy is in the range of 0.250-0.310 nm.

(13) The polarizing plate of Item (12), wherein a free volume parameterof the retardation film determined by positron annihilation lifetimespectroscopy is in the range of 1.0-2.0.

(14) The polarizing plate of Item (12), wherein a free volume parameterof the retardation film determined by positron annihilation lifetimespectroscopy is in the range of 1.2-1.8.

(15) The polarizing plate of any one of Items (12) to (14), wherein thecellulose ester is an ester of mixed carboxylic acids having 2-22 carbonatoms.

(16) The polarizing plate of any one of Items (12) to (15), wherein Rois in the range of 20-300 nm and Rt is in the range of 70-400 nm.

(17) The polarizing plate of any one of Items (12) to (16), wherein adimensional variation of the retardation film after it is stored under acondition of 80° C. and 90% RH is within ±2%.

(18) A polarizing plate having thereon a stretched cellulose ester filmcontaining a plasticizer and a cellulose ester,

wherein

a free volume radius of the stretched cellulose ester film determined bypositron annihilation lifetime spectroscopy is in the range of0.250-0.310 nm;

a free volume parameter of the stretched cellulose ester film determinedby positron annihilation lifetime spectroscopy is in the range of1.0-2.0;

the stretched cellulose ester film is produced by heat treating the filmat 105-150° C. under a rate of atmosphere replacement ratio of 12times/h or more, after the film is dried until an amount of residualsolvent decreases to less than 0.3%.

(19) A liquid crystal display having a direct illumination backlightunit and the polarizing plate of any one of Items (12) to (18).

(20) A method for producing a retardation film containing the steps of:

casting a dope containing a plastcizer and a cellulose ester on asupport to form a web;

peeling the web from the support;

stretching the web while the web still contains a solvent;

further drying the web until an amount of residual solvent decreases to0.3%; and

heat treating the web at 105-155° C. under a rate of atmospherereplacement of 12 times/h or more or more preferably 12-45 times/h whilethe web is transported, to obtain a prescribed free volume radius and aprescribed free volume parameter.

The characteristics of the present invention will now be described.

One of the aspects of the present invention is a polarizing plate havingon one surface of which a retardation film containing a plasticizer anda cellulose ester, wherein a free volume radius of the retardation filmdetermined by positron annihilation lifetime spectroscopy is in therange of 0.250-0.310 nm. Further, it is preferably the polarizationplate having the retardation film of which a free volume parameter1.0-2.0.

The free volume in the present invention represents vacant area which isnot occupied by the cellulose ester chain. This free volume can bemeasured using positron annihilation lifetime spectroscopy. Morespecifically, by measuring the time from injection of positrons into acellulose ester film to the annihilation of the positrons, namelyannihilation lifetime of positrons, size and numerical concentration offree volume holes are nondestructively estimated from the annihilationlifetime of positrons.

<Measurement of Free Volume Radius by Positron Annihilation LifetimeSpectroscopy, and Free Volume Parameter>

A positron annihilation lifetime and relative intensity were measuredunder the following measurement condition.

(Measurement Condition).

-   -   Positron source: 22NaCl (intensity: 1.85 MBq)    -   Gamma-ray detector: Plastic scintillator+Photomultiplier tube.    -   Apparatus time resolution: 290 ps    -   Measurement temperature: 23° C.    -   Total number of counts: 1 million counts    -   Specimen size: 20 mm×15 mm×2 mm        20 pieces of 20 mm×15 mm sized films were piled to prepare an        about 2 mm thick sample. The sample was dried under vacuum 24        hours.    -   Irradiation area: About 10 mm in diameter    -   Time per channel: 23.3 ps/ch

According to the above measurement condition, positron annihilationlifetime spectroscopy was carried out. Using a nonlinear least-squaremethod, three components of cellulose ester films were analyzed. Whenthe annihilation times were referred to as, in small order, τ1, τ2 andτ3 and the corresponding intensities were referred to as I₁, I₂ and I₃(I₁+I₂+I₃=100%), respectively, using the largest annihilation time τ3, afree volume radius R₃ (nm) was determined using the following formula.The larger the τ3 value is, the larger the free volume is estimated tobe.τ3=(½)[1−{R ₃/(R ₃+0.166)}+(½π)sin{2πR ₃/(R ₃+0.166)}]⁻¹where, 0.166 (nm) represents the thickness of the electronic layer whichis exuding from the wall of a hole.

The free volume parameter VP was determined by the following formula.V3={( 4/3)π(R3)³} (nm³)VP=−I3(%)×V3 (nm³)

Since I3 (%) is equivalent to the relative number concentration of ahole here, VP is equivalent to the relative amount of holes.

The above measurements were repeated twice and the mean values werecalculated for the determination.

Evaluation of a free volume in polymer by positron annihilationspectroscopy is explained in, for example, MATERIAL STAGE vol. 4, No. 5,2004, pp. 21-25, The TRC News, No. 80 (July, 2002) PP. 20-22 (publishedby Toray Research Center), and “BUNSEKI (Analysis)”, 1988, pp. 11-20”.

The free volume radius of the retardation film of the present inventionis preferably 0.250-0.310 nm and is more preferably 0.270-0.305 nm. Inan industrial process, it is rather difficult to produce a celluloseester retardation film having a free volume radius of less than 0.250 nmor a free volume parameter less than 1.0. The retardation film of thepresent invention having a free volume radius of 0.250-0.310 nm ispreferable since it enables the effect of the present invention.However, in the retardation films prepared by the conventionalpreparation method, it has been difficult to find a retardation filmhaving a free volume radius of not more than 0.31 nm. The free volumeparameters are preferably in the range of 1.0-2.0, and more preferablyin the range of 1.2-1.8. When the free volume parameter is less than1.8, patch of retardation becomes difficult to occur.

The method to control the free volume radius and the free volumeparameter of a retardation film containing a plasticizer and a celluloseester within the prescribed ranges is not specifically limited, however,they may be controlled by the following method.

A retardation film having a free volume radius of 0.250-0.310 and a freevolume parameter of 1.0-2.0 determined by positron annihilation lifetimespectroscopy is obtained by a method containing the steps of:

casting a dope containing a plastcizer and a cellulose ester on asupport to form a web;

peeling the web from the support;

stretching the web while the web still contains a solvent;

further drying the web until an amount of residual solvent decreases to0.3%; and

heat treating the web at 105-155° C. under a rate of atmospherereplacement of 12 times/h or more or more preferably 12-45 times/h whilethe web is transported.

The rate of atmosphere replacement is the number of times replacing theatmosphere of a heat treatment chamber by fresh-air per unit time,provided that the volume of the heat treatment chamber is expressed as V(m³) and the amount of fresh-air sent to the heat treatment chamber isexpressed as FA (m³/h). Fresh-air does not include the air which isrecycled and circulating, among the air sent to the heat treatmentchamber but includes the air containing no evaporated solvent norevaporated plasticizer, or the air from which evaporated solvent orevaporated plasticizer are removed.Rate of atmosphere replacement=FA/V (times/h)

When the heat treatment temperature exceeds 155° C., or when it is lowerthan 105° C., the effect of the present invention tends not be acquired.

As the operating temperature, it is still more preferable that theoperating temperature is in the range of 110-150° C. Further, preferableis that the heat treatment is carried out under the condition in whichthe rate of atmosphere replacement is 12 times/h or more. When it isless than 12 times/h, the effect of the present invention tends not beacquired.

When the rate of atmosphere replacement is 12 times/h or more, theconcentration of the plasticizer evaporated from the retardation film inthe atmosphere is thoroughly reduced, accordingly, re-deposition of theplasticizer to the retardation film is also reduced. This is assumed tocontribute in attaining the effect of the present invention. When therate of atmosphere replacement is increased more than necessary, theproduction cost increases and due to the fluttering of the web,retardation patch increases. Accordingly, it is not recommended that therate of atmosphere replacement is increased more than necessary,however, after the web was thoroughly dried and the amount of residualsolvent is considerably decreased, it can be increased. However, therate of atmosphere replacement of 45 times/h or more is not practicalsince the production cost drastically increases. The heat treatmentunder the rate of atmosphere replacement of 12 times/h or more ispreferably carries out within 1 minute-1 hour. If the treatment time isless than 1 minute, the free volume radius within a prescribed range maybe difficult to obtain, while, when it is not more than 1 hour, thechange of retardation value is allowable.

Further, in this process, a pressurizing treatment of the retardationfilm in the thickness direction may also be effectively carried out tocontrol the free energy volume radius and the free volume parameterwithin more preferable range. The pressure is preferably 0.5-10 kPa. Theamount of residual solvent at the stage when the pressurizing treatmentis carried out is preferably less than 0.3. At 0.3% or more, the effectof the present invention cannot fully be reduced, although flatness ofthe retardation film may be improved.

When a retardation film is not subjected to the above mentionedtreatments, the free volume radius may become larger than 0.315.

The present invention will now be further detailed, however, the presentinvention is not limited thereto.

<Cellulose Ester>

The number average molecular weight (Mn) of the cellulose ester used forthe present invention is preferably 80000-200000. It is more preferably100000-200000 and still more preferably 150000-200000.

The ratio of weight average molecular weight (Mw) to number averagemolecular weight (Mn), Mw/Mn, of the cellulose ester used for thepresent invention is preferably in the range of 1.2-3.0, and morepreferably in the range of 1.7-2.2.

The average molecular weight and the molecular weight distribution ofcellulose ester can be measured by a well-known method using highperformance liquid chromatography. A number average molecular weight andweight-average molecular weight can be calculated using these values,and the ratio (Mw/Mn) can be calculated.

The measurement condition is as follows.

-   -   Solvent: Methylene chloride    -   Column: Shodex K806, K805, K803G (produced by Showa Denko K.K.)    -   Column temperature: 25° C.    -   Sample concentration: 0.1% by weight    -   Detector: RI Model 504 (produced by GL Sciences Inc.)    -   Pump: L6000 (produced by Hitachi, Ltd.)    -   Feed rate: 1.0 ml/min    -   Calibration: Standardized polystyrene STK        standard Polystyrene (made by TOSOH CORP.). A calibration curve        is drawn by using 13 samples in the range of Mw=1,000,000-500.        The intervals in Mw values among the 13 samples are preferably        equal.

An aliphatic-carboxylic-acid ester, an aromatic-carboxylic-acid ester ora mixed carboxylic acid ester thereof having from 2 to around 22 carbonatoms is preferably used for the cellulose ester of the presentinvention, since the effect of the present invention is notablyacquired.

Specifically, a lower fatty acid ester of cellulose is preferable,wherein the lower fatty acid represents a fatty acid having 6 carbonatoms or less. Examples of a specific lower fatty acid ester ofcellulose include: cellulose acetate, cellulose propionate, cellulosebutyrate, cellulose acetate phthalate and mixed fatty acid esters, forexample, cellulose acetate propionate and cellulose acetate butylate,which are disclosed in JP-A No. 10-45804, No. 8-231761 and U.S. Pat. No.2,319,052. Of these, cellulose acetate propionate, cellulose acetatebutylate, and cellulose acetate propionate butyrate are specificallypreferable as the lower fatty acid ester of cellulose of the presentinvention. These cellulose esters may also be used in combination. Sincethese cellulose esters are amorphous-like, unlike cellulose triacetate,they are specifically preferably used in the present invention.

The total acylation degree is preferably in the range of 2.4-2.9. Thecellulose ester of the present invention specifically preferablycontains an acyl group having 2-22 carbon atoms as a substituent andsatisfies the following Formulas (I) and (II), provided that Xrepresents an acetylation degree and Y represents an substitution degreewith an acyl group having 3-22 carbon atoms:2.4≦X+Y≦2.9  Formula (I)0≦X≦2.5  Formula (II)

Among these, specifically preferable is cellulose acetate propionatewith 1.7≦X≦2.5 and 0.1≦Y≦1.2 (total substitution degree is representedby X+Y). The part which is not replaced with an acyl group generallyexists as a hydroxyl group. These compound are prepared by a knownmethod in the art.

The acylation degree of a cellulose ester is determined according to themethod specified in ASTM-D 817-96.

Cellulose ester is prepared using cotton linter, wood pulp or kenaf asstarting materials which may be used alone or in combination. It isspecifically preferable to use a cellulose ester prepared from cottonlinter (hereafter merely referred to as linter) or from wood pulp aloneor in combination.

These cellulose esters may also be used by mixing with each other in anyratio. In case, an acid anhydride (acetic anhydride, propionicanhydride, and butyric anhydride) is used as an acylation agent,cellulose ester can be prepared through a common reaction using anorganic acid such as acetic acid and an organic solvent such asmethylene chloride, in the presence of a protic catalyst such assulfuric acid.

In the case of an acetyl cellulose, it is necessary to prolong theacetylation duration in order to obtain a higher degree of acetylation,however, a too long acetylation duration may result in a undesirablereaction such as cutting off of a polymer chain or a decomposition of anacyl group. Accordingly, the acetylation duration should be limitedwithin an appropriate range, however, specifying a degree of acetylationwith an acetylation duration is not fully recommended because theacetylation conditions differ when a different reactor or differentequipment is utilized. In general, during decomposition of a polymer,the distribution of the molecular weight increases, so that, also in thecase of a cellulose ester, the degree of decomposition can be specifiedby the commonly used Mw/Mn value, where Mw represents a weight averagemolecular weight and Mn denotes a number average molecular weight.Namely, the Mw/Mn value can be used as one of the parametersrepresenting the degree of acetylation reaction at which thedecomposition of the polymer has not been excessive and, at the sametime, sufficient acetylation has already been achieved.

An example of a preparation method of cellulose ester is describedbelow. Cotton linter of 100 weight parts as a starting material ofcellulose was crushed, and after adding 40 weight parts of acetic acid,the system was pretreated for activation at 36° C. for 20 minutes.Thereafter, 8 weight parts of sulfuric acid, 260 weight parts of aceticanhydride and 350 weight parts of acetic acid were added, after whichesterification was performed at 36° C. for 120 minutes. The system wassaponification ripened at 63° C. for 35 minutes after being neutralizedwith 11 weight parts of 24% magnesium acetate aqueous solution to obtainacetyl cellulose. After the system was stirred with adding ten times ofan acetic acid solution (acetic, acid/water=1/1, based on weight ratio)at ambient temperature for 160 minutes, the resulting solution wasfiltered and dried to obtain a purified acetyl cellulose having anacetyl substitution degree of 2.75. The obtained acetyl celluloseexhibited Mn of 92,000, Mw of 156,400, and Mw/Mn of 1.7. In a similarmanner, cellulose esters having different substitution degrees anddifferent Mw/Mn ratios can be synthesized by controlling theesterification conditions of cellulose ester (temperature, duration andstirring rate) as well as hydrolysis conditions. Removal of lowmolecular weight component by refining and removal of non-acetizedcomponent by filtering from the prepared cellulose ester are alsopreferably carried out.

For the prepared cellulose ester, the following treatments arepreferably carried out, namely, (i) removal of low molecular weightportion by refining; or (ii) removal of unacetylated portion orlow-acetylated portion by filtering.

Further, a cellulose ester of mixed acids can be prepared by a reactionemploying the method described in JP-A 10-45804. The acyl substitutiondegree can be measured according to the definition of ASTM-D817-96.

The properties of a cellulose ester are influenced by residual amountsof metal components which may be originated from the water used in themanufacturing process. Metal components which may cause insoluble coresshould preferably be minimal. Metal ions of iron(Fe), calcium(Ca),magnesium(Mg) and other metals may form insoluble cores by forming saltsin combination with decomposition products of polymers which maypossibly contain organic acid groups. Accordingly these metal ionsshould be minimal. The amount of iron is preferably less than 1 ppm.Calcium easily forms a coordinated compound, namely a complex, with acidcomponents such as carbonic acid, sulfuric acid, or with variousligands, and causes much insoluble scum (insoluble residue andturbidity).

The preferable amount of calcium is commonly less than 60 ppm, and ismore preferably from 0 to 30 ppm. Too much magnesium may also causeinsoluble residue, and the preferable amount is from 0 to 70 ppm, morepreferably from 0 to 20 ppm. After an absolutely dry cellulose esterfilm is treated with a microdigest wet-decomposer (sulfuric acid-nitricacid decomposing) followed by being subjected to alkali fusion, theamounts of iron, calcium, magnesium are determined by means of IPC-AES(Inductively Coupled Plasma-Atomic Emission Spectroscopy).

<Plasticizers>

The total content of one or more plasticizers contained in theretardation film of the present invention is preferably 1-20% by weightand more preferably 3-18% by weight based on the total solid amount ofthe retardation film.

The plasticizer used in the retardation film of the present invention isnot specifically limited. However, examples of a preferable plasticizerinclude: a phosphate plasticizer, a glycolate plasticizer, a citrateplasticizer, a phthalate plasticizer, a polyalcohol ester plasticizer, apolycarboxylate plasticizer, a fatty acid ester plasticizer, a polyesterplasticizer and a polyuretane plasticizer.

Examples of a phosphate plasticizer include: triphenyl phosphate,tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenylphosphate, diphenyl biphenyl phosphate, trioctyl phosphate and tributylphosphate. As for a glycolate plasticizer, alkylphthalylalkyl glycolatesare preferably used. Examples of an alkylphthalylalkyl glycolateinclude: methylphthalylmethyl glycolatel ethylphthalylethyl glycolate,propylphthalylpropyl glycolate, butylphthalylbutyl glycolate,octylphthalyloctyl glycolate, methylphthalylethyl glycolate,ethylphthalylmethyl glycolate, ethylphthalylpropyl glycolate,methylphthalylbutyl glycolate, ethylphthalylbutyl glycolate,butylphthalylmethyl glycolate, butylphthalylethyl glycolate,propylphthalylbutyl glycolate, butylphthalylpropyl glycolate,methylphthalyloctyl glycolate, ethylphthalyloctyl glycolate,octylphthalylmethyl glycolate and octylphthalylethyl glycolate.

Examples of a phthalate plasticizer include: diethyl phthalate,dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutylphthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexylphthalate and dicyclohexyl terephthalate.

Examples of a citrate plasticizer include: acetyltrimethyl citrate,acetyltriethyl citrate and acetyltributyl citrate.

Examples of a fatty acid ester plasticizer include: butyl oleate,methylacetyl ricinoleate and dibutyl sebacate.

A polycarboxylate plasticizer is also used preferably. It is preferableto add one of polycarboxylates disclosed in JP-A No. 2002-265639,paragraph number [0015]-[0020] as a plasticizer.

Under the circumstances of high temperature and high humidity, whenadditives, such as a plasticizer, deposit and volatilize out of a film,the property of loosing the film weight is referred to as volatility. Inthe conventional cellulose ester film, this volatility has been largeresulting in lowing the function of the display. In the presentinvention, the volatility under a condition of 80° C. and 90% RH ispreferably not more than ±2% by weight based on the total weight of theplasticizer.

Examples of a plasticizer exhibiting volatility under a condition of 80°C. and 90% RH of ±2% by weight include: a poly alcohol esterplasticizer, a polyester plasticizer and a polyuretane plasticizer.

A polyalcohol ester plasticizer is a plasticizer containing an ester ofan aliphatic polyalcohol having a valence of two or more and amonocarboxylic acid, and it preferably contains an aromatic ring or acycloalkyl ring in the molecule. It is preferably an aliphaticpolyalcohol ester having a valence of 2-20.

The polyalcohol used for the present invention is represented with thefollowing general formula (i).R₁—(OH)_(n)  General formula (i)wherein, R₁ represents an organic group having a valence of n, nrepresents a positive integer of two or more, and an OH group representsalcoholic or a phenolic hydroxyl group. It is preferable that the numberof carbon atoms of the polyalcohol are five or more. Examples ofpreferable polyalcohol include: adonitol, arabitol, ethylene glycol,diethylene glycol, triethylene glycol, tetraethylene glycol,1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropyleneglycol, 1,2-butanediol, 1,3-butanediol, 1.4-butanediol, dibutyleneglycol, 1,2,4-bunanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol,galactitol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol,trimethylolpropane, trimethylolethane and xylitol, but the invention isnot limited thereto. Specifically, triethylene glycol, tetraethyleneglycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane and xylitol are preferable.

As the monocarboxylic acid to be used in the polyalcohol ester, a knownaliphatic monocarboxylic acid, alicyclic monocarboxylic acid andaromatic monocarboxylic acid may be employed, though the monocarboxylicacid is not specifically limited. Specifically, aliphatic monocarboxylicacid and aromatic monocarboxylic acid are preferable, because themoisture permeability and the volatility are reduced.

Examples of the preferable monocarboxylic acid are listed below but theinvention is not limited thereto.

A straight or branched chain carboxylic acid having 1 to 32 carbon atomsis preferably employed. The number of carbon atoms is more preferablyfrom 1-20, and specifically preferably from 1-10. The addition of aceticacid is preferable for raising the compatibility with a cellulose ester,and the mixing of acetic acid with another carboxylic acid is alsopreferable.

As the preferable aliphatic monocarboxylic acid, saturated fatty acidssuch as acetic acid, propionic acid, butylic acid, valeric acid, caproicacid, enantic acid, caprylic acid, pelargonic acid, capric acid,2-ethyl-hexane acid, undecylic acid, lauric acid, tridecylic acid,myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid,stearic acid, nonadecanic acid, arachic acid, behenic acid, lignocelicacid, cerotic acid, heptacosanic acid, montanic acid, melisic acid andlacceric acid; and unsaturated fatty acids such as undecylenic acid,oleic acid, sorbic acid, linolic acid, linolenic acid and arachidonicacid can be exemplified.

Examples of preferable alicyclic carboxylic acid include cyclopentenecarboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylicacid and derivatives thereof.

Examples of preferable aromatic carboxylic acid include ones formed byintroducing an alkyl group into the benzene ring of benzoic acid such asbenzoic acid and toluic acid, an aromatic monocarboxylic acid having twoor more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid and tetralin carboxylic acid and derivatives of them,and benzoic acid is specifically preferable.

The molecular weight of the polyalcohol is preferably from 300 to 1,500,and more preferably from 350 to 1000 though the molecular weight is notspecifically limited. Larger molecular weight is preferable for storageability, while smaller molecular weight is preferable for compatibilitywith cellulose ester.

The carboxylic acid to be employed in the polyalcohol ester may be onekind or a mixture of two or more kinds of them.

Concrete examples of the polyalcohol ester are listed below.

Polyester plasticizers disclosed in JP-A No. 2002-22956, paragraphnumbers [0051]-[0056] are used in the present invention. Polyuretaneplasticizers disclosed in JP-A No. 2003-171499, paragraph numbers[0031]-[0039] are also preferable.

Further, the aromatic terminal ester plasticizers represented by Formula(I) are also preferable.B-(G-A)_(n)-G-B  Formula (I)where B represents benzene monocarboxylic acid group, G represents analkylene glycol group having 2-12 carbon atoms or an oxyalkylene glycolgroup having 4-12 carbon atoms, A represents an alkylene dicarboxylicacid having 4-12 carbon atoms, and n represents an integer of 0 or more.A compound represented by Formula (I) is prepared through a reactionsimilar to the preparation reaction of a common polyester plasticizer.

Examples of a benzene monocarboxylic acid component of the aromaticterminal ester of the present invention include: benzoic acid,p-tert-butyl benzoic acid, o-toluic acid, m-toluic acid, p-toluic acid,dimethyl benzoic acid, ethyl benzoic acid, n-propyl benzoic acid,aminobenzoic acid and acetoxy benzoic acid, which may be used alone orin combination of two or more acids.

Examples of an alkylene glycol component having 2-12 carbon atoms of thethe aromatic terminal ester of the present invention include: ethyleneglycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol,1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol,1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (also known asneopentylglycol), 2,2-diethyl-1,3-propanediol (also known as3,3-dimethylol pentane), 2-n-butyl-2-ethyl-1,3-propanediol (also knownas 3,3-dimethylol heptane), 3-methyl-1,5-pentanediol-1,6-hexanediol,2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol,2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol,1,12-octadecanediol, which may be used alone or in combination of two ormore glycols.

Examples of an oxyalkylene glycol component having 4-12 carbon atoms ofthe aromatic terminal ester of the present invention include: diethyleneglycol, triethylene glycol, tetraethylene glycol, dipropylene glycol andtriropylene glycol, which may be used alone or in combination of two ormore glycols.

Examples of an alkylene dicarboxylic acid component having 4-12 carbonatoms of the aromatic terminal ester of the present invention include:succinic acid, maleic acid, the fumaric acid, glutaric acid, adipicacid, azelaic acid, sebacic acid and dodecane dicarboxylic acid, whichmay be used alone or in combination of two or more acids.

The number average molecular weight of the aromatic terminal ester usedin the present invention is preferably 0.250-2000, and more preferably300-1500. The acid value of the aromatic terminal ester used in thepresent invention is preferably not more than 0.5 mgKOH/g and morepreferably not more than 0.3 mgKOH/g. The hydroxyl value of the aromaticterminal ester used in the present invention is preferably not more than25 mgKOH/g and more preferably not more than 15 mgKOH/g.

(Acid Value and Hydroxyl Value of Aromatic Terminal Ester)

“Acid value” means the milligrams of potassium hydroxide required toneutralize the acid (carboxyl group existing in a specimen) included in1 g of sample. Alternatively, “hydroxyl value” means the milligrams ofpotassium hydroxide required to neutralize the acetic acid bonded to thehydroxyl groups after acetylation of 1 g of sample. The acid value andthe hydroxyl value are measured based on JIS K0070.

Examples of a synthetic method of an aromatic terminal ester plasticizerare shown below:

<Sample No. 1 (Aromatic Terminal Ester Sample)>

In a container, 365 weight parts (2.5 moles) of adipic acid, 418 weightparts (5.5 moles) of 1,2-propylene glycol, 610 weight parts (5 moles) ofbenzoic acid and 0.30 weight part of tetra-isopropyl titanates (as acatalyst) were loaded at a time, and, while stirring under a nitrogenatmosphere, the mixture was heated at 130-250° C. until the acid valuedecreased to 2 or less. The excess monovalent alcohol was refluxed usinga reflux condenser and produced water was continuously removed. Then,the container was evacuated to 100 mmHg and, finally, to 3 mmHg at200-230° C., while the distillate was removed. The product was filteredto obtain an aromatic terminal ester having the following features:

Viscosity (25° C.): 815 mPa·s

Acid value: 0.4

<Sample No. 2 (Aromatic Terminal Ester Sample)>

An aromatic terminal ester having the following features was prepared inthe same manner as Sample No. 1 except that 365 weight parts (2.5 moles)of adipic acid, 610 weight parts (5 moles) of benzoic acid, 583 weightparts (5.5 moles) of diethylene glycol and 0.45 weight part oftetra-isopropyl titanates (as a catalyst) were used.

Viscosity (25° C.): 90 mPa·s

Acid value: 0.05

<Sample No. 3 (Aromatic Terminal Ester Sample)>

An aromatic terminal ester having the following features was prepared inthe same manner as Sample No. 1 except that 365 weight parts (2.5 moles)of adipic acid, 610 weight parts (5 moles) of benzoic acid, 737 weightparts (5.5 moles) of dipropylene glycol and 0.40 weight part oftetra-isopropyl titanates (as a catalyst) were used.

Viscosity (25° C.): 134 mPa·s

Acid value: 0.03

Among these plasticizers, preferably two or more plasticizers arecontained in the retardation film of the present invention, whereby lossof plasticizer from the retardation film is reduced. The reason is notfully clear, however, it is because (i) the amount of one kind ofplasticizer can be decreased; and (ii) an interaction between the twoplasticizers or between a plasticizer and cellulose ester may havesuppressed loss of plasticized from from the retardation film.

<UV Absorbing Agent>

The cellulose ester film of the present invention preferably contains aUV absorbing agent in order to improve the durability of an LCD byabsorbing UV rays of which wavelength is 400 nm or less. Thetransmittance at a wavelength of 370 nm is preferably not more than 10percent and is more preferably not more than 5 percent and still morepreferably not more than 2 percent.

Examples of a UV absorbing agent used in the present invention include:oxybenzophenone, benzotriazol, salicylic acid ester, benzophenone,cyanoacrylate, triazine, nickel complex salt and inorganic particles.

UV absorbing agents preferably used in the present invention include abenzotriazole UV absorbing agent and a benzophenone UV absorbing agent,both of which are extremely transparent and have a superior effect ofpreventing degradation of the polarizing plate or liquid crystaldisplay. Among these, a benzotriazole UV absorbing agent having reducedcoloring is specifically preferrable. Specific examples of a UVabsorbing agent include TINUVIN 109, TINUVIN 171, TINUVIN 326, TINUVIN327 and TINUVIN 328 which are manufactured by Chiba Specialty ChemicalsCo. However, the present invention is not limited thereto.

For example, as a benzotriazole UV absorbing agent, the compoundrepresented by the following Formula (A) is applicable.

wherein R₁, R₂, R₃, R₄, and R₅ may be the same or may be different, andeach represent a hydrogen atom, a halogen atom, a nitro group, ahydroxyl group, an alkyl group, an alkenyl group, an aryl group, analkoxy group, an acyloxyl group, an aryloxy group, an alkylthio group,an arylthio group, a mono or di alkylamino group, an acylamino group, ora heterocyclic group of 5-6 member; and R4 and R5 may be combined toform a 5-6 membered ring.

Each of the above mentioned groups may have an arbitrary substituent.

Examples of an UV absorbing agent used for the present invention isgiven to below, however, the present invention is not limited thereto.

UV-1: 2-(2′-hydroxy-5′-methylphenyl) benzotriazole

UV-2: 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl) benzotriazole

UV-3: 2-(2′-hydroxy-3′-tert-butyl-5′-methylphenyl) benzotriazole

UV-4: 2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-5-chlorobenzotriazole

UV-5:2-(2′-hydroxy-3′-(3″,4″,5″,6″-tetrahydrophthalimidomethyl)-5′-methylphenyl)benzotriazole

UV-6: 2,2-methylenebis(4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazole-2-yl) phenol)

UV-7: 2-(2′-hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole

UV-8: 2-(2H-benzotriazole-2-yl)-6-(n- and iso-dodecyl)-4-methylphenol(TINUVIN171, product of Ciba Specialty Chemicals Inc.)

UV-9: Mixture ofoctyl-3-[3-tert-butyl-4-hydroxy-5-(chloro-2H-benzotriazole-2-yl) phenyl]propionate and2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate (TINUVIN109, product of Ciba Specialty Chemicals Inc.)

Further, examples of the UV absorbing agents preferably used in thepresent invention include a benzophenone UV absorbing agent and atriazine UV absorbing agent, of these, a triazine UV absorbing agent isspecifically preferable.

As a benzotriazole UV absorbing agent, the compound represented by thefollowing Formula (B) is preferably used.

wherein Y represents a hydrogen atom, a halogen atom, an alkyl group, analkenyl group, an alkoxyl group, or a phenyl group, of these, the alkylgroup, the alkenyl group, and the phenyl group may have a substituent; Arepresents a hydrogen atom, an alkyl group, an alkenyl group, a phenylgroup, a cycloalkyl group, an alkylcarbonyl group, an alkylsulfonylgroup, or —CO(NH)n-1-D group, wherein D represents an alkyl group, analkenyl group or a phenyl group which may have a substituent; and m andn each represent 1 or 2.

In the above description, the alkyl group represents, for example, anormal or branched aliphatic group having not more than 24 carbon atoms,the alkoxyl group represents, for example, an alkoxyl group having notmore than 18 carbon atoms, and the alkenyl group represents, forexample, an alkenyl group having not more than 16 carbon atoms, such asan allyl group or a 2-butenyl group. Examples of a substituent to thealkyl group, the alkenyl group, and the phenyl group include, forexample: a halogen atom such as a chlorine atom, a bromine atom and afluorine atom, a hydroxyl group and a phenyl group (the phenyl group mayfurther have an alkyl group or a halogen atom as a substituent).

Specific examples of a benzophenone related compound represented byFormula (B) are shown below, however, the present invention is notlimited thereto.

UV-10: 2,4-dihydroxy benzophenone

UV-11: 2,2′-dihydroxy-4-methoxybenzophenone

UV-12: 2-hydroxy-4-methoxy-5-sulfobenzophenone

UV-13: Bis (2-methoxy-4-hydroxy-5-benzoylphenylmethane)

A compound having a 1,3,5-triazine ring is also preferably used as an UVabsorbing agent of the optical film of the present invention.

Among the compounds having a 1,3,5-triazine ring, specificallypreferable is a compound represented by Formula (C).

wherein X₁ represents a single bond, —NR₄—, —O—, or —S—, X₂ represents asingle bond, —NR₅—, —O—, or —S—; X₃ represents a single bond, —NR₆—,—O—, or —S—; R₁, R₂, and R₃ each represents an alkyl group, an alkenylgroup, an aryl group, or a heterocyclic group; and R₄, R5, and R₆ eachrepresents a hydrogen atom, an alkyl group, an alkenyl group, an arylgroup, or a heterocyclic group. The compound represented by Formula (C)is preferably a melamine compound.

With respect to a melamine compound, in Formula (C), X₁, X₂, and X₃ are—NR₄—, —NR₅—, and —NR₆—, respectively, or X₁, X₂, and X₃ each is asingle bond; and R₁, R₂, and R₃ each is a heterocyclic group which havea free radical in a nitrogen atom. Further, —X, —R₁, —X₂—R₂, and —X₃—R₃are preferably the same substituent. R₁, R₂, and R₃ each is specificallypreferably an aryl group and R₄, R₅, and R₆ each is specificallypreferably a hydrogen atom.

The above alkyl group is more preferably a chain alkyl group than acyclic alkyl group and a linear chain alkyl group is more preferablethan a branched chain alkyl group.

The number of carbon atoms in an alkyl group is preferably 1-30, morepreferably, 1-20, further more preferably 1-10, still more preferably1-8, and the most preferably 1-6. The alkyl group may have asubstituent.

Specific examples of a substituent include: a halogen atom, an alkoxylgroup (for example, a methoxy group, an ethoxy group and anepoxyethyloxy group) and an acyloxy group (for example, an acryloyloxygroup, a methacryloyloxy group). It is more preferable for the abovealkenyl group to be a catenoid alkenyl group from a cyclic alkenylgroup.

The above alkenyl group is more preferably a chain alkenyl group than acyclic alkenyl group and a linear chain alkenyl group is more preferablethan a branched chain alkenyl group. The number of carbon atoms in anThe number of carbon atoms in an alkyl group is preferably 2-30, morepreferably, 2-20, further more preferably 2-10, still more preferably2-8, and the most preferably 2-6. The alkenyl group may have asubstituent.

Specific examples of a substituent include: a halogen atom, an alkoxylgroup (for example, a methoxy group, an ethoxy group or an epoxyethyloxygroup), or an acyloxy group (for example, an acryloyloxy group and amethacryloyloxy group).

With respect to the above aryl group, preferable are a phenyl group anda naphthyl group, and more preferable is a phenyl group. The aryl groupmay have a substituent.

Specific examples of substituent include: a halogen atom, a hydroxylgroup, a cyano group, a nitro group, a carboxyl group, an alkyl group,an alkenyl group, an aryl group, an alkoxyl group, an alkenyloxy group,an aryloxy group, an acyloxy group, an alkoxycarbonyl group, analkenyloxycarbonyl group, an aryloxycarbonyl group, a sulfamoyl group,an alkyl substituted sulfamoyl group, an alkenyl substituted sulfamoylgroup, an aryl substituted sulfamoyl group, a sulfonamides group, acarbamoyl group, an alkyl substituted carbamoyl group, an alkenylsubstituted carbamoyl group, an aryl substituted carbamoyl group, anamide group, an alkylthio group, an alkenylthio group, an arylthio groupand an acyl group.

The alkyl group mentioned here is common the alkyl group mentionedabove.

The alkyl parts of the alkoxy group, the acyloxy group, thealkoxycarbonyl group, the alkyl substituted sulfamoyl group, thesulfonamides group, the alkyl substituted carbamoyl group, the amidegroup, the alkylthio group, and the acyl group mentioned here are alsocommon to the alkyl group mentioned above.

The alkenyl group mentioned here is common to the alkenyl groupmentioned above.

The alkenyl parts of the alkenyloxy group, the acyloxy group, thealkenyloxycarbonyl group, the alkenyl substituted sulfamoyl group, thesulfonamides group, the alkenyl substituted carbamoyl group, the amidegroup, the alkenylthio group, and the acyl group mentioned here are alsocommon to the alkenyl group mentioned above.

Specific examples of the above aryl group include: a phenyl group, anα-naphthyl group, a β-naphthyl group, a 4-methoxyphenyl group, a3,4-diethoxyphenyl group, a 4-octyloxyphenyl group and a4-dodecyloxyphenyl group.

The specific examples for the above aryloxy group, the acyloxy group,the aryloxycarbonyl group, the aryl substituted sulfamoyl group, thesulfonamides group, the aryl substituted carbamoyl group, the amidegroup, the arylthio group, and the acyl group are common to those of theabove aryl group.

When X₁, X₂ and X₃ each is —NR—, —O—, or —S—, the heterocyclic group ispreferably has aromaticity.

The heterocycle in a heterocyclic group having aromaticity is generallyan unsaturated heterocycle and preferably has the largest number ofunsaturated bonds. The heterocycle is preferably a 5 membered ring, a 6membered ring or a 7 membered ring, more preferably a 5 membered ring ora 6 membered ring, and most preferably a 6 membered ring.

The hetero atom contained in the heterocyclic ring is preferably an Natom, an S atom or an O atom and specifically preferably an N atom.

As a heterocyclic ring having aromaticity, a pyridine ring (as aheterocyclic group, for example, a 2-pyridyl group or a 4-pyridyl groupis listed) is specifically preferable. The heterocyclic, group may havethe substituent. Examples of the substituent of the heterocyclic groupare common to those of the above aryl part.

When X₁, X₂, and X₃ each is a single bond, the heterocyclic grouppreferably has a free radical on the nitrogen atom. The heterocyclicgroup having a free radical on the nitrogen atom is preferably a 5membered ring, a 6 membered ring or a 7 membered ring, more preferably a5 membered ring or a 6 membered ring, and most preferably a 5 memberedring. The heterocyclic group may have a plurality of nitrogen atoms.

The heterocyclic group may have a heteroatom other than nitrogen (forexample, an O atom or an S atom. The heteroclic group may have asubstituent. Examples of the substituent of the heterocyclic group arecommon to those of the above aryl part.

Examples of a heterocyclic group having a free radical on a nitrogenatom are shown below:

The molecular weight of a compound having a 1,3,5-triazine ring ispreferably 300-2000. The boiling point of this compound is preferably260° C. or more. A boiling point can be measured using a commercialmeasuring assembly (for example, TG/DTA100 produced by Seiko InstrumentsInc.).

Example of a compound having a 1,3,5-triazine ring is shown below:

A plurality of R shown below represent the same group.(1)-(12)

wherein R represents one of the following groups:(1) Butyl(2) 2-methoxy-2-ethoxyethyl(3) 5-undecenyl(4) Phenyl(5) 4-ethoxycarbonylphenyl(6) 4-butoxyphenyl(7) p-biphenylyl(8) 4-pyridyl(9) 2-naphthyl(10) 2-methylphenyl(11) 3,4-dimethoxyphenyl(12) 2-furil(13)

wherein R represents one of the following groups:(14)-(79)

wherein R represents one of the following groups:(14) Phenyl(15) 3-ethoxycarbonylphenyl(16) 3-butoxyphenyl(17) m-biphenylyl(18) 3-phenylthiophenyl(19) 3-chlorophenyl(20) 3-benzoylphenyl(21) 3-acetoxyphenyl(22) 3-benzoyloxyphenyl(23) 3-phenoxycarbonylphenyl(24) 3-methoxyphenyl(25) 3-anilinophenyl(26) 3-isobutyrylaminophenyl(27) 3-phenoxycarbonylaminophenyl(28) 3-(3-ethylureido)phenyl(29) 3-(3,3-diethylureido)phenyl(30) 3-methylphenyl(31) 3-phenoxyphenyl(32) 3-hydroxyphenyl(33) 4-ethoxycarbonylphenyl(34) 4-butoxyphenyl(35) p-biphenylyl(36) 4-phenylthiophenyl(37) 4-chlorophenyl(38) 4-benzoylphenyl(39) 4-acetoxyphenyl(40) 4-benzoyloxyphenyl(41) 4-phenoxycarbonylphenyl(42) 4-methoxyphenyl(43) 4-anilinophenyl(44) 4-isobutyrylaminophenyl(45) 4-phenoxycarbonylaminophenyl(46) 4-(3-ethylureido)phenyl(47) 4-(3,3-diethylureido)phenyl(48) 4-methylphenyl(49) 4-phenoxyphenyl(50) 4-hydroxyphenyl(51) 3,4-diethoxcarbonylphenyl(52) 3,4-dibutoxyphenyl(53) 3,4-diphenylphenyl(54) 3,4-diphenylthiophenyl(55) 3,4-dichlorophenyl(56) 3,4-dibenzoylphenyl(57) 3,4-diacetoxyphenyl(58) 3,4-dibenzoyloxyphenyl(59) 3,4-diphenoxycarbonylphenyl(60) 3,4-dimethoxyphenyl(61) 3,4-dianilinophenyl(62) 3,4-dimethylphenyl(63) 3,4-diphenoxyphenyl(64) 3,4-dihydroxyphenyl(65) 2-naphthyl(66) 3,4,5-triethoxycarbonylphenyl(67) 3,4,5-tributoxy henyl(68) 3,4,5-triphenylphenyl(69) 3,4,5-triphenylthiophenyl(70) 3,4,5-trichlorophenyl(71) 3,4,5-tribenzoylphenyl(72) 3,4,5-triacetoxyphenyl(73) 3,4,5-tribenzoyloxyphenyl(74) 3,4,5-triphenoxycarbonylphenyl(75) 3,4,5-trimethoxyphenyl.(76) 3,4,5-trianilinophenyl(77) 3,4,5-trimethylphenyl(78) 3,4,5-triphenoxyphenyl(79) 3,4,5-trihydroxyphenyl(80)-(145)

wherein R represents one of the following groups:(80) Phenyl(81) 3-ethoxycarbonylphenyl(82) 3-butoxyphenyl(83) m-biphenylyl(84) 3-phenylthiophenyl(85) 3-chlorophenyl(86) 3-benzoylphenyl(87) 3-acetoxyphenyl(88) 3-benzoyloxyphenyl(89) 3-phenoxycarbonylphenyl(90) 3-methoxyphenyl,(91) 3-anilinophenyl(92) 3-isobutyrylaminophenyl(93) 3-phenoxycarbonylaminophenyl(94) 3-(3-ethylureido)phenyl(95) 3-(3,3-diethylureido)phenyl(96) 3-methylphenyl(97) 3-phenoxyphenyl(98) 3-hydroxyphenyl.(99) 4-ethoxycarbonylphenyl(100) 4-butoxyphenyl(101) p-biphenylyl(102) 4-phenylthiophenyl(103) 4-chlorophenyl(104) 4-benzoylphenyl(105) 4-acetoxyphenyl(106) 4-benzoyloxyphenyl(107) 4-phenoxycarbonylphenyl(108) 4-methoxyphenyl(109) 4-anilinophenyl(110) 4-isobutyrylaminophenyl(111) 4-phenoxycarbonylaminophenyl(112) 4-(3-ethylureido)phenyl(113) 4-(3,3-diethylureido)phenyl(114) 4-methylphenyl(115) 4-phenoxyphenyl(116) 4 Hydroxyphenyl(117) 3,4-diethoxcarbonylphenyl(118) 3,4-dibutoxyphenyl(119) 3,4-diphenylphenyl(120) 3,4-diphenylthiophenyl(121) 3,4-dichlorophenyl(122) 3,4-dibenzoylphenyl(123) 3,4-diacetoxyphenyl(124) 3,4-dibenzoyloxyphenyl(125) 3,4-diphenoxycarbonylphenyl(126) 3,4-dimethoxyphenyl(127) 3,4-dianilinophenyl(128) 3,4-dimethylphenyl(129) 3,4-diphenoxyphenyl(130) 3,4-dihydroxyphenyl(131) 2-naphthyl(132) 3,4,5-triethoxycarbonylphenyl(133) 3,4,5-tributoxyphenyl(134) 3,4,5-triphenylphenyl.(135) 3,4,5-triphenylthiophenyl(136) 3,4,5-trichlorophenyl(137) 3,4,5-tribenzoylphenyl(138) 3,4,5-triacetoxyphenyl(139) 3,4,5-tribenzoyloxyphenyl(140) 3,4,5-triphenoxycarbonylphenyl(141) 3,4,5-trimethoxyphenyl(142) 3,4,5-trianilinophenyl(143) 3,4,5-trimethylphenyl(144) 3,4,5-triphenoxyphenyl(145) 3,4,5-trihydroxyphenyl(146)-(164)

wherein R represents one of the following groups:(146) Phenyl(147) 4-ethoxycarbonylphenyl(148) 4-butoxyphenyl(149) p-biphenylyl(150) 4-phenylthiophenyl(151) 4-chlorophenyl(152) 4-benzoylphenyl(153) 4-acetoxyphenyl(154) 4-benzoyloxyphenyl(155) 4-phenoxycarbonylphenyl(156) 4-methoxyphenyl(157) 4-anilinophenyl(158) 4-isobutyrylaminophenyl(159) 4-phenoxycarbonylaminophenyl(160) 4-(3-ethylureido)phenyl(161) 4-(3,3-diethylureido)phenyl(162) 4-methylphenyl(163) 4-phenoxyphenyl(164) 4-hydroxyphenyl(165)-(183)

(165) Phenyl(166) 4-ethoxycarbonylphenyl(167) 4-butoxyphenyl(168) p-biphenylyl(169) 4-phenylthiophenyl(170) 4-chlorophenyl(171) 4-benzoylphenyl(172) 4-acetoxyphenyl(173) 4-benzoyloxyphenyl(174) 4-phenoxycarbonylphenyl(175) 4-methoxyphenyl(176) 4-anilinophenyl(177) 4-isobutyrylaminophenyl(178) 4-phenoxycarbonylaminophenyl(179) 4-(3-ethylureido)phenyl(180) 4-(3,3-diethylureido)phenyl(181) 4-methylphenyl(182) 4-phenoxyphenyl(183) 4-hydroxyphenyl(184)-(202)

wherein R represents one of the following groups:(184) Phenyl(185) 4-ethoxycarbonylphenyl(186) 4-butoxyphenyl(187) p-biphenylyl(188) 4-phenylthiophenyl(189) 4-chlorophenyl(190) 4-benzoylphenyl(191) 4-acetoxyphenyl(192) 4-benzoyloxyphenyl(193) 4-phenoxycarbonylphenyl(194) 4-methoxyphenyl(195) 4-anilinophenyl(196) 4-isobutyrylaminophenyl(197) 4-phenoxycarbonylaminophenyl(198) 4-(3-ethylureido)phenyl(199) 4-(3,3-diethylureido)phenyl(200) 4-methylphenyl(201) 4-phenoxyphenyl(202) 4 Hydroxyphenyl(203)-(221)

wherein R represents one of the following groups:(203) Phenyl(204) 4-ethoxycarbonylphenyl(205) 4-butoxyphenyl(206) p-biphenylyl(207) 4-phenylthiophenyl(208) 4-chlorophenyl(209) 4-benzoylphenyl(210) 4-acetoxyphenyl(211) 4-benzoyloxyphenyl(212) 4-phenoxycarbonylphenyl(213) 4-methoxyphenyl(214) 4-anilinophenyl(215) 4-isobutyrylaminophenyl(216) 4-phenoxycarbonylaminophenyl(217) 4-(3-ethylureido)phenyl(218) 4-(3,3-diethylureido)phenyl(219) 4-methylphenyl(220) 4-phenoxyphenyl(221) 4-hydroxyphenyl(222)-(419)

wherein R represents one of the following groups:(222) Phenyl(223) 4-butylphenyl(224) 4-(2-methoxy-2-ethoxyethyl)phenyl(225) 4-(5-nonenyl)phenyl(226) p-biphenylyl(227) 4-ethoxycarbonylphenyl(228) 4-butoxyphenyl(229) 4-methylphenyl(230) 4-chlorophenyl(231) 4-phenylthiophenyl(232) 4-benzoylphenyl(233) 4-acetoxyphenyl(234) 4-benzoyloxyphenyl(235) 4-phenoxycarbonylphenyl(236) 4-methoxyphenyl(237) 4-anilinophenyl(238) 4-isobutyrylaminophenyl(239) 4-phenoxycarbonylaminophenyl(240) 4-(3-ethylureido)phenyl(241) 4-(3,3-diethylureido)phenyl(242) 4-phenoxyphenyl(243) 4 Hydroxyphenyl(244) 3-butylphenyl(245) 3-(2-methoxy-2-ethoxyethyl)phenyl(246) 3-(5-nonenyl)phenyl(247) m-biphenylyl(248) 3-ethoxycarbonylphenyl(249) 3-butoxyphenyl(250) 3-methylphenyl(251) 3-chlorophenyl(252) 3-phenylthiophenyl(253) 3-benzoylphenyl(254) 3-acetoxyphenyl(255) 3-benzoyloxyphenyl(256) 3-phenoxycarbonylphenyl(257) 3-methoxyphenyl(258) 3-anilinophenyl(259) 3-isobutyrylaminophenyl(260) 3-phenoxycarbonylaminophenyl(261) 3-(3-ethylureido)phenyl(262) 3-(3,3-diethylureido)phenyl(263) 3-phenoxyphenyl(264) 3 Hydroxyphenyl(265) 2-butylphenyl(266) 2-(2-methoxy-2-ethoxyethyl)phenyl(267) 2-(5-nonenyl)phenyl(268) o-biphenylyl(269) 2-ethoxycarbonylphenyl(270) 2-butoxyphenyl(271) 2-methylphenyl(272) 2-chlorophenyl(273) 2-phenylthiophenyl(274) 2-benzoylphenyl(275) 2-acetoxyphenyl(276) 2-benzoyloxyphenyl(277) 2-phenoxycarbonylphenyl(278) 2-methoxyphenyl(279) 2-anilinophenyl(280) 2-isobutyrylaminophenyl(281) 2-phenoxycarbonylaminophenyl(282) 2-(3-ethylureido)phenyl(283) 2-(3,3-diethylureido)phenyl(284) 2-phenoxyphenyl(285) 2-hydroxyphenyl(286) 3,4-dibutylphenyl(287) 3,4-di (2-methoxy-2-ethoxyethyl) phenyl(288) 3,4-diphenylphenyl(289) 3,4-diethoxcarbonyl phenyl(290) 3,4-didodecyloxyphenyl(291) 3,4-dimethylphenyl(292) 3,4-dichloro phenyl(293) 3,4-dibenzoylphenyl(294) 3,4-diacetoxyphenyl(295) 3,4-dimethoxyphenyl(296) 3,4-di-N-methylaminophenyl(297) 3,4-diisobutyrylaminophenyl(298) 3,4-diphenoxyphenyl(299) 3,4-dihydroxyphenyl(300) 3,5-dibutylphenyl(301) 3,5-di(2-methoxy-2-ethoxyethyl)phenyl(302) 3,5-diphenylphenyl(303) 3,5-diethoxycarbonylphenyl(304) 3,5-didodecyloxyphenyl(305) 3,5-dimethylphenyl(306) 3,5-dichlorophenyl(307) 3,5-dibenzoylphenyl(308) 3,5-diacetoxyphenyl(309) 3,5-dimethoxyphenyl(310) 3,5-di-N-methylaminophenyl(311) 3,5-diisobutyrylaminophenyl(312) 3,5-diphenoxyphenyl(313) 3,5-dihydroxyphenyl(314) 2,4-dibutylphenyl(315) 2,4-di(2-methoxy-2-ethoxyethyl)phenyl(316) 2,4-diphenylphenyl(317) 2,4-diethoxycarbonylphenyl(318) 2,4-didodecyloxyphenyl(319) 2,4-dimethylphenyl(320) 2,4-dichlorophenyl(321) 2,4-dibenzoylphenyl(322) 2,4-diacetoxyphenyl(323) 2,4-dimethoxyphenyl(324) 2,4-di-N-methylaminophenyl(325) 2,4-diisobutyrylaminophenyl(326) 2,4-diphenoxyphenyl(327) 2,4-dihydroxyphenyl(328) 2,3-dibutylphenyl(329) 2,3-di(2-methoxy-2-ethoxyethyl)phenyl(330) 2,3-diphenylphenyl(331) 2,3-diethoxycarbonylphenyl(332) 2,3-didodecyloxyphenyl(333) 2,3-dimethylphenyl(334) 2,3-dichlorophenyl(335) 2,3-dibenzoylphenyl(336) 2,3-diacetoxyphenyl(337) 2,3-dimethoxyphenyl(338) 2,3-di-N-methylaminophenyl(339) 2,3-diisobutyrylaminophenyl(340) 2,3-diphenoxyphenyl(341) 2,3-dihydroxy phenyl(342) 2,6-dibutylphenyl(343) 2,6-di(2-methoxy-2-ethoxyethyl)phenyl(344) 2,6-diphenylphenyl(345) 2,6-diethoxycarbonylphenyl(346) 2,6-didodecyloxyphenyl(347) 2,6-dimethylphenyl(348) 2,6-dichlorophenyl(349) 2,6-dibenzoylphenyl(350) 2,6-diacetoxyphenyl(351) 2,6-dimethoxyphenyl(352) 2,6-di-N-methylaminophenyl(353) 2,6-diisobutyrylaminophenyl(354) 2,6-diphenoxyphenyl(355) 2,6-dihydroxyphenyl(356) 3,4,5-tributylphenyl(357) 3,4,5-tri(2-methoxy-2-ethoxyethyl)phenyl(358) 3,4,5-triphenylphenyl(359) 3,4,5-triethoxycarbonylphenyl(360) 3,4,5-tridodecyloxyphenyl(361) 3,4,5-trimethylphenyl(362) 3,4,5-trichlorophenyl(363) 3,4,5-tribenzoylphenyl(364) 3,4,5-triacetoxyphenyl(365) 3,4,5-trimethoxyphenyl(366) 3,4,5-tri-N-methylaminophenyl(367) 3,4,5-triisobutyrylaminophenyl(368) 3,4,5-triphenoxyphenyl(369) 3,4,5-trihydroxyphenyl(370) 2,4,6-tributylphenyl(371) 2,4,6-tri(2-methoxy-2-ethoxyethyl)phenyl(372) 2,4,6-triphenylphenyl(373) 2,4,6-triethoxycarbonylphenyl(374) 2,4,6-tridodecyloxyphenyl(375) 2,4,6-trimethylphenyl(376) 2,4,6-trichlorophenyl(377) 2,4,6-tribenzoylphenyl(378) 2,4,6-triacetoxyphenyl(379) 2,4,6-trimethoxyphenyl(380) 2,4,6-tri-N-methylaminophenyl(381) 2,4,6-triisobutyrylaminophenyl(382) 2,4,6-triphenoxyphenyl(383) 2,4,6-trihydroxyphenyl(384) pentafluorophenyl(385) pentachlorophenyl(386) pentamethoxyphenyl(387) 6-N-methylsulfamoyl-8-methoxy-2-naphthyl(388) 5-N-methylsulfamoyl-2-naphthyl(389) 6-N-phenylsulfamoyl-2-naphthyl(390) 5-ethoxy-7-N-methylsulfamoyl-2-naphthyl(391) 3-methoxy-2-naphthyl(392) 1-ethoxy-2-naphthyl(393) 6-N-phenylsulfamoyl-8-methoxy-2-naphthyl(394) 5-methoxy-7-N-phenyl sulfamoyl-2-naphthyl(395) 1-(4-methylphenyl)-2-naphthyl(396) 6,8-di-N-methylsulfamoyl-2-naphthyl(397) 6-N-2-acetoxyethylsulfamoyl-8-methoxy-2-naphthyl(398) 5-acetoxy-7-N-phenylsulfamoyl-2-naphthyl(399) 3-benzoyloxy-2-naphthyl(400) 5-acetylamino-1-naphthyl(401) 2-methoxy-1-naphthyl(402) 4-phenoxy-1-naphthyl(403) 5-N-methylsulfamoyl-1-naphthyl(404) 3-N-methylcarbamoyl-4-hydroxy-1-naphthyl(405) 5-methoxy-6-N-ethylsulfamoyl-1-naphthyl(406) 7-tetradecyloxy-1-naphthyl(407) 4-(4-methylphenoxy)-1-naphthyl(408) 6-N-methylsulfamoyl-1-naphthyl(409) 3-N,N-dimethylcarbamoyl-4-methoxy-1-naphthyl(410) 5-methoxy-6-N-benzylsulfamoyl-1-naphthyl(411) 3,6-di-N-phenylsulfamoyl-1-naphthyl(412) methyl(413) ethyl(414) butyl(415) octyl(416) dodecyl(417) 2-butoxy-2-ethoxyethyl(418) benzyl(419) 4-methoxybenzyl

wherein R represents one of the following groups:(424) methyl(425) phenyl(426) butyl

wherein R represents one of the following groups:(430) methyl(431) ethyl(432) butyl(433) octyl(434) dodecyl(435) 2-butoxy-2-ethoxyethyl(436) benzyl(437) 4-methoxybenzyl

In the present invention, a melamine polymer may be used as a compoundhaving 1,3,5-triazine ring. A melamine polymer is preferably preparedthrough a polymerization reaction of a melamine compound represented byFormula (D) and a carbonyl compound.

In the above reaction scheme, R¹¹, R¹², R¹³, R¹⁴, R¹⁵, and R¹⁶ eachrepresents a hydrogen atom, an alkyl group, an alkenyl group, an arylgroup, or a heterocyclic group.

The above alkyl group, an alkenyl group, an aryl group, heterocyclicgroups, and these substituents are common to those aforementioned inrelation to Formula (C).

The polymerization reaction of a melamine compound and carbonylcompounds is carried out in same manner as a usual synthetic method of amelamine resin (for example, a melamine formaldehyde resin). Acommercially available melamine polymer (melamine resin) may also beused.

The molecular weight of a melamine polymer is preferably 2000 to400,000. Examples of a repeat unit of a melamine polymer will be shownbelow:(MP-1)-(MP-50)

MP-1:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂OHMP-2:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂OCH₃MP-3:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-4:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-5:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂NHCOCH═CH₂MP-6:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-7:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂OCH₃MP-8:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂OCH₃MP-9:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂OCH₃MP-10:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂OCH₃MP-11:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂OCH₃MP-12:R¹³, R¹⁴, R¹⁶:CH₂OCH₃; R¹⁵:CH₂OHMP-13:R¹³, R¹⁶:CH₂OCH₃; R¹⁴, R¹⁵:CH₂OHMP-14:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-i-C₄H₉MP-15:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂O-i-C₄H₉MP-16:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-17:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂O-i-C₄H₉MP-18:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-19:R¹³, R¹⁴, R¹⁶:CH₂C-i-C₄H₉; R¹⁵:CH₂OHMP-20:R¹³, R¹⁶:CH₂O-i-C₄H₉; R¹⁴, R¹⁵:CH₂OHMP-21:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP 22:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂O-n-C₄H₉MP-23:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-24:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂O-n-C₄H₉MP-25:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-26:R¹³, R¹⁴, R¹⁶:CH₂O-n-C₄H₉; R¹⁵:CH₂OHMP-27:R¹³, R¹⁶:CH₂O-n-C₄H₉; R¹⁴, R¹⁵:CH₂OHMP-28:R¹³, R¹⁴:CH₂OH; R¹⁵:CH₂OCH₃; R¹⁶:CH₂O-n-C₄H₉MP-29:R¹³, R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂OCH₃MP-30:R¹³, R¹⁶:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂O-n-C₄H₉MP-31:R¹³:CH₂OH; R¹⁴, R¹⁵:CH₂OCH₃; R¹⁶:CH₂-n-C₄H₉MP-32:R¹³:CH₂OH; R¹⁴, R¹⁶:CH₂OCH₃; R¹⁵:CH₂O-n-C₄H₉MP-33:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-34:R¹³:CH₂OH; R¹⁴, R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂OCH₃MP-35:R¹³, R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-36:R¹³, R¹⁶:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉MP-37:R¹³:CH₂OCH₃; R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-38:R¹³, R¹⁶:CH₂O-n-C₄H₉; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OHMP-39:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂NHCOCH═CH₂MP-40:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂O-n-C₄H₉MP-41:R¹³:CH₂OH; R¹⁴:CH₂O-n-C₄H₉; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂OCH₃MP-42:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂NHCOCH═CH₂MP-43:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂O-n-C₄H₉MP-44:R¹³:CH₂O-n-C₄H₉; R¹⁴ CH₂CH₃; R¹⁵:CH₂OH; R¹⁶:CH₂NHCOCH═CH₂MP-45:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃;R¹⁶:CH₂NHCOCH═CH₂MP-46:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-47:R¹³:CH₂OH; R¹⁴:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂OCH₃MP-48:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃;R¹⁶:CH₂NHCOCH═CH₂MP-49:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-50:R¹³:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH;R¹⁶:CH₂NHCOCH═CH₂(MP-51)-(MP-100)

MP-51:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂OHMP-52:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂OCH₃MP-53:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-54:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-55:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂NHCOCH═CH₂MP-56:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-57:R¹³, R¹⁴, R¹⁵:CH₂H; R¹⁶:CH₂OCH₃MP-58:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂OCH₃MP-59:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂OCH₃MP-60:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂OCH₃MP-61:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂OCH₃MP-62:R¹³, R¹⁴, R¹⁶:CH₂OCH₃; R¹⁵:CH₂OHMP-63:R¹³, R¹⁶:CH₂OCH₃; R¹⁴, R¹⁵:CH₂OHMP-64:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-i-C₄H₉MP-65:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂O-i-C₄H₉MP-66:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-67:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂O-i-C₄H₉MP-68:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-69:R¹³, R¹⁴, R¹⁶:CH₂O-i-C₄H₉; R¹⁵:CH₂OHMP-70:R¹³, R¹⁶:CH₂O-i-C₄H₉; R¹⁴, R¹⁵:CH₂OHMP-71:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-72:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂O-n-C₄H₉MP-73:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-74:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂O-n-C₄H₉MP-75:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-76:R¹³, R¹⁴, R¹⁶:CH₂O-n-C₄H₉; R¹⁵:CH₂OHMP-77:R¹³, R¹⁶:CH₂O-n-C₄H₉; R¹⁴, R¹⁵:CH₂OHMP-78:R¹³, R¹⁴:CH₂OH; R¹⁵:CH₂OCH₃; R¹⁶:CH₂O-n-C₄H₉MP-79:R¹³, R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂OCH₃MP-80:R¹³, R¹⁶:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂O-n-C₄H₉MP-81:R¹³:CH₂OH; R¹⁴, R¹⁵:CH₂OCH₃; R¹⁶:CH₂O-n-C₄H₉MP-82:R¹³:CH₂OH; R¹⁴, R¹⁶:CH₂OCH₃; R¹⁵:CH₂O-n-C₄H₉MP-83:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-84:R¹³:CH₂OH; R¹⁴, R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂OCH₃MP-85:R¹³, R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-86:R¹³, R¹⁶:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉MP-87:R¹³:CH₂OCH₃; R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-88:R¹³, R¹⁶:CH₂O-n-C₄H₉; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OHMP-89:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂NHCOCH═CH₂MP-90:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂O-n-C₄H₉MP-91:R¹³:CH₂OH; R¹⁴:CH₂O-n-C₄H₉; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂OCH₃MP-92:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂NHCOCH═CH₂MP-93:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂O-n-C₄H₉MP-94:R¹³:CH₂O-n-C₄H₉; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH; R¹⁶:CH₂NHCOCH═CH₂MP-95:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃;R¹⁶:CH₂NHCOCH═CH₂MP-96:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-97:R¹³:CH₂OH; R¹⁴:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂OCH₃MP-98:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃;R¹⁶:CH₂NHCOCH═CH₂MP-99:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-100:R¹³:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH;R¹⁶:CH₂NHCOCH═CH₂(MP-101)-(MP-150)

MP-101:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂OHMP-102:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂OCH₃MP-103:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂O-i-C₄,HMP-104:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-105:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂NHCOCH═CH₂MP-106:R¹³, R¹⁴R¹⁵, R¹⁶:CH₂NHCO(CH₂—)₇CH═CH(CH₂)₇CH₃MP-107:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂OCH₃MP-108:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂OCH₃MP-109:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂OCH₃MP-110:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂OCH₃MP-111:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂OCH₃MP-112:R¹³, R¹⁴, R¹⁶:CH₂OCH₃; R¹⁵:CH₂OHMP-113:R¹³, R¹⁶:CH₂OCH₃; R¹⁴, R¹⁵:CH₂OHMP-114:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-i-C₄H₉MP-115:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂O-i-C₄H₉MP-116:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-117:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂O-i-C₄HMP-118:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-119:R¹³, R¹⁴, R¹⁶:CH₂O-i-C₄H₉; R¹⁵:CH₂OHMP-120:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-122:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂-n-C₄H₉MP-123:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-124:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂O-n C₄H₉MP-125:R¹³:CH₂OH; R¹⁴, R¹⁵R¹⁶:CH₂O-n-C₄H₉MP-126:R¹³, R¹⁴, R¹⁶:CH₂O-n-C₄H₉; R¹⁵:CH₂OHMP-127:R¹³R¹⁶:CH₂O-n-C₄H₉; R¹⁴, R¹⁵:CH₂OHMP-128:R¹³, R¹⁴:CH₂OH; R¹⁵:CH₂OCH₃; R¹⁶:CH₂O-n-C₄H₉MP-129:R¹³, R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂OCH₃MP-130:R¹³, R¹⁶:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂-n-C₄H₉MP-131:R¹³:CH₂OH; R¹⁴, R¹⁵:CH₂OCH₃; R¹⁶:CH₂O-n-C₄H₉MP-132:R¹³:CH₂OH; R¹⁴, R¹⁶:CH₂OCH₃; R¹⁵:CH₂O-n-C₄H₉MP-133:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-134:R¹³:CH₂OH; R¹⁴, R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂CH₃MP-135:R¹³, R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-136:R¹³, R¹⁶:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉MP-137:R¹³:CH₂OCH₃; R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-138:R¹³, R¹⁶:CH₂O-n-C₄H₉; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OHMP-139:R¹³:CH₂OH; R¹⁴:CH₂ OCH₃; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂NHCOCH═CH₂MP-140:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂O-n-C₄H₉MP-141:R¹³:CH₂OH; R¹⁴:CH₂O-n-C₄H₉; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂OCH₃MP-142:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂NHCOCH═CH₂MP-143:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂O-n-C₄H₉MP-144:R¹³:CH₂O-n-C₄H₉; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH; R¹⁶:CH₂NHCOCH═CH₂MP-145:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇ CH₃;R¹⁶:CH₂NHCOCH═CH₂MP-146:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-147:R¹³:CH₂OH; R¹⁴:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂OCH₃MP-148:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃;R¹⁶:CH₂NHCOCH═CH₂MP-149:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-150:R¹³:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH;R¹⁶:CH₂NHCOCH═CH₂(MP-151)-(MP-200)

MP-151:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂OHMP-152:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂OCH₃MP-153:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-154:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-155:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂NHCOCH═CH₂MP-156:R¹³, R¹⁴, R¹⁵, R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-157:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂OCH₃MP-158:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂OCH₃MP-159:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂OCH₃MP-160:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂OCH₃MP-161:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂OCH₃MP-162:R¹³, R¹⁴, R¹⁶:CH₂OCH₃; R¹⁵:CH₂OHMP-163:R¹³, R¹⁶:CH₂OCH₃; R¹⁴, R¹⁵:CH₂OHMP-164:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-i-C₄H₉MP-165:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂O-i-C₄H₉MP-166:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-167:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂O-i-C₄H₉MP-168:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂O-i-C₄H₉MP-169:R¹³, R¹⁴, R¹⁶:CH₂O-i-C₄H₉; R¹⁵:CH₂OHMP-170:R¹³, R¹⁶:CH₂O-i-C₄H₉; R¹⁴, R¹⁵:CH₂OHMP-171:R¹³, R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-172:R¹³, R¹⁴, R¹⁶:CH₂OH; R¹⁵:CH₂O-n-C₄H₉MP-173:R¹³, R¹⁴:CH₂OH; R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-174:R¹³, R¹⁶:CH₂OH; R¹⁴, R¹⁵:CH₂O-n-C₄H₉MP-175:R¹³:CH₂OH; R¹⁴, R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-176:R¹³, R¹⁴, R¹⁶:CH₂O-n-C₄H₉; R¹⁵:CH₂OHMP-177:R¹³, R¹⁶:CH₂O-n-C₄H₉; R¹⁴, R¹⁵:CH₂OHMP-178:R¹³, R¹⁴:CH₂OH; R¹⁵:CH₂ OCH₃; R¹⁶:CH₂O-n-C₄H₉MP-179:R¹³, R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂OCH₃MP-180:R¹³, R¹⁶:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂-n-C₄H₉MP-181:R¹³:CH₂OH; R¹⁴, R¹⁵:CH₂OCH₃; R¹⁶:CH₂O-n-C₄H₉MP-182:R¹³:CH₂OH; R¹⁴, R¹⁶:CH₂OCH₃; R¹⁵:CH₂O-n-C₄H₉.MP-183:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵, R¹⁶:CH₂O-n-C₄H₉MP-184:R¹³:CH₂OH; R¹⁴, R¹⁵:CH₂O-n-C₄H₉; R¹⁵:CH₂OCH₃MP-185:R¹³, R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-186:R¹³, R¹⁶:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉MP-187:R¹³:CH₂OCH₃; R¹⁴, R¹⁵:CH₂OH; R¹⁶:CH₂O-n-C₄H₉MP-188:R¹³, R¹⁶:CH₂O-n-C₄H₂; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OHMP-189:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂NHCOCH═CH₂MP-190:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂O-n-C₄H₉MP-191:R¹³:CH₂OH; R¹⁴:CH₂O-n-C₄H₉; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂OCH₃MP-192:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂O-n-C₄H₉; R¹⁶:CH₂NHCOCH═CH₂MP-193:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCOCH═CH₂; R¹⁶:CH₂O-n-C₄H₉MP-194:R¹³:CH₂O-n-C₄H₉; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH; R¹⁶:CH₂NHCOCH═CH₂MP-195:R¹³:CH₂OH; R¹⁴:CH₂OCH₃; R¹⁵:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃;R¹⁶:CH₂NHCOCH═CH₂MP-196:R¹³:CH₂OH; R¹⁴ CH₂OCH₃; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-197:R¹³:CH₂OH; R¹⁴:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂OCH₃MP-198:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃;R¹⁶:CH₂NHCOCH═CH₂MP-199:R¹³:CH₂OCH₃; R¹⁴:CH₂OH; R¹⁵:CH₂NHCOCH═CH₂;R¹⁶:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃MP-200:R¹³:CH₂NHCO(CH₂)₇CH═CH(CH₂)₇CH₃; R¹⁴:CH₂OCH₃; R¹⁵:CH₂OH;R¹⁶:CH₂NHCOCH═CH₂

In the present invention, a copolymer containing two or more kinds ofabove repeat units is also usable. Two or more kinds of homopolymer or acopolymer may also be used in combination.

A compound having two or more kinds of 1,3,5-triazine rings may be usedand two or more discotic compounds (for example, a compound having a1,3,5-triazine ring and a compound having a porphyrin moiety) are alsousable.

These additives are preferably used in an amount of 0.2-30% by weight,more preferably 1-20% by weight based on the weight of the celluloseester film.

A triazine compound represented by Formula (I) of JP-A No. 2001-235621may be also preferably used for the cellulose ester film of the presentinvention.

The cellulose ester film of the present invention preferably containstwo or more kinds of UV absorbing agents.

As a UV absorbing agent, a polymer UV absorbing agent may also bepreferably used, and specifically a UV absorbing agent described in JP-ANo. 6-148430 polymer type is preferable.

The addition methods of said UV absorbing agents are as follows. Theymay be dissolved in organic solvents such as alcohol (e.g., methanol,ethanol or butanol), methylene chloride, methyl acetate, acetone anddioxolane, and the resulting solution of which is added to a dope.Alternatively, they may be added directly to a dope. UV absorbing agentssuch as inorganic powder, which are not soluble in organic solvents, maybe dispersed into a mixture of organic solvents and cellulose ester,employing a dissolver or a sand mill, and then added to a dope.

The employed amount of UV absorbing agents may vary depending on thetype of UV absorbing agent or on the use condition, however, when thedried layer thickness of the cellulose ester film is 30-200 μm, thecontent of a UV absorbing agent is preferably 0.5-4.0% by weight basedon the weight of the cellulose ester film, and more preferably 0.6-2.0%by weight.

<Particles>

The cellulose ester film of the present invention preferably containsmicroparticles.

As for the microparticles use in the present invention, examples ofinorganic microparticles include: silicon dioxide microparticles,titanium dioxide microparticles, aluminium oxide microparticles,zirconium oxide microparticles, calcium carbonate microparticles, talcmicroparticles, clay microparticles, calcinated caolin microparticles,calcinated calcium silicate microparticles, hydration calcium silicatemicroparticles, aluminium silicate microparticles, magnesium silicatemicroparticles, and calcium phosphate microparticles. Microparticlescontaining silicon are preferable, because low turbidity of the film isobtained. Silicon dioxide microparticles are specifically preferable.

The mean diameter of primary particles is preferably from 5 to 50 nm,and more preferably from 7 to 20 nm. The particle should preferablyexist as an aggregated secondary particle of a diameter from 0.05 to 0.3μm. The content of the particle in a cellulose ester film is preferablyfrom 0.05 to 1 percent by weight, and is more preferably from 0.1 to 0.5percent. In a multi-layered cellulose ester film prepared by aco-casting method, a major part of the particles should preferably existnear the surface.

Microparticles of silicon dioxide available on the market include, forexample: AEROSIL R972, R927V, R974, R812, 200, 200V, 300, R202, OX50 andTT600 which are manufacture by Nippon Aerosil Co., Ltd.

Microparticles of zirconium oxide available on the market include, forexample: AEROSIL R976 and R811 manufacture by Nippon Aerosil Co., Ltd.

Microparticles of polymer available on the market include, for example:silicone resin, fluorine-contained resin and acryl resin. Among these,silicone resin, especially three dimensionally networked silicone resinis preferably used. Examples of silicone resins include: TOSPERL 103,105, 108, 120, 145, 3120 and 240, which are manufactured by ToshibaSilicone Co., Ltd.

Among the microparticles listed above, AEROSIL 200V and AEROSIL R972Vare specifically preferable with respect to exhibiting a lower frictioncoefficient while the low turbidity is maintained. Kinetic frictioncoefficient of the rear side of an actinic ray curable resin layer ofthe present invention is preferably not more than 1.0.

<Antioxidant>

In the present invention, the following antioxidants are preferablyused.

As the antioxidant, a phenol-containing antioxidant, a phosphoricacid-containing antioxidant, a sulfur-containing antioxidant, astabilizer against heat processing and an oxygen scavenger areemployable, and among them the phenol-containing antioxidant, andparticularly an alkyl-substituted phenol-containing antioxidant arepreferable. By using an antioxidant as described above in theretardation film, the coloring and the lowering in the strength of theretardation film which may occur in the film production process byheating by being oxidized can be prevented without loosing thetransparency and the heat resistance of the retardation film. Theseantioxidants may be employed alone or in combination of two or morekinds thereof. The adding amount is optionally decided within the rangein which the effect of the invention is maintained, and is preferablyfrom 0.001 to 5 weight parts, and more preferably from 0.01 to 1 weightpart, in 100 weight parts of the polymer of the present invention.

As the antioxidant, a hindered phenol antioxidant is preferred, whichincludes 2,6-dialkylphenol derivatives disclosed in U.S. Pat. No.4,839,405, columns 12-14. Such the compounds include ones represented byFormula (1).

In the above formula, R1, R2 and R3 each represent a further substitutedor unsubstituted alkyl group. Specific examples of the hindered phenolcompound include: n-octadecyl3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, n-octadecyl 3-(3,5-dit-butyl-4-hydroxyphenyl)acetate, n-octadecyl 3,5-dit-butyl-4-hydroxybenzoate, n-hexyl3,5-di-t-butyl-4-hydroxyphenylbenzoate, n-dodecyl3,5-di-t-butyl-4-hydroxyphenylbenzoate, neododecyl3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,dodecylβ(3,5-di-t-butyl-4-hydroxyphenyl)propionate, ethylα-(4-hydroxy-3,5-di-t-butylphenyl)isobutylate, octadecylα-(4-hydroxy-3,5-di-t-butylphenyl)isobutylate, octadecylα-(4-hydroxy-3,5-di-t-butyl-4-hydroxyphenyl)propionate,2-(n-octylthio)ethyl 3,5-di-t-butyl-e-hydroxybenzoate,2-(n-octylthio)ethyl 3,5-di-t-butyl-4-hydroxyphenylacetate,2-(n-octadecylthio)ethyl 3,5-di-t-butyl-4-hydroxybenzoate,2-(2-hydroxyethylthio)ethyl 3,5-di-t-butyl-4-hydroxybenzoate,diethylglycol bis-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,2-(n-octadecylthio)ethyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,stearylamido N,N-bis[ethylene3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate], n-butyliminoN,N-bis-[ethylene 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate],2-(2-stearoylo-xyethylthio)ethyl 3,5-di-t-butyl-4-hydroxybenzoate,2-(2-stearoylo-xyethylthio)ethyl7-(3-methyl-5-t-butyl-4-hydroxyphenyl)heptanoate, 1,2-propylene glycolbis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], ethylene glycolbis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate], neopentyl glycolbis-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], ethylene glycolbis-(3,5-di-t-butyl-4-hydroxyphenylacetate), glycerol1-n-octadecanoate-2,3-bis-(3,5-di-t-butyl-4-hdyroxyphenylacetate),pentaerythrytol tetrakis[3-(3,5-di-t-butyl-4′-hydroxyphenyl)propionate],1,1,1-trimethylolethanetris[3-(3,5-di-t-butyl-hydroxyphenyl)propionate], sorbitolhexa-[3-(3,5-di-t-butyl-hydroxyphenyl)propionate], 2-hydroxyethyl7-(3,5-di-t-butyl-hydroxyphenyl)propionate, 2-stearoyloxyethyl7-(3,5-di-t-butyl-hydroxyphenyl)-heptanoate, 1,6-n-hexanediolbis-[(3,5-di-t-butyl-4-hydroxyphenyl)propionate] and pentaerythrytoltetrakis(3,5-di-t-butyl-4-hydroxycinnamate). The above described typehindered phenol antioxidant is, for example, available on the marketunder the commercial name of Irganox 1076 and Irganox 1010 of CibaSpecialty Chemicals.

Concrete examples of other antioxidant include a phosphor typeantioxidant such as trisnonylphenyl phosphite andtris(2,4-di-tert-butylphenyl) phosphite, a sulfur type antioxidant suchas dilauryl 3,3′-thiopropionate, dimyristyl, 3,3′-thiopropionate,distearyl 3,3′-thiopropionate and pentaerythrytyltetrakis(3-laurylthiopropionate), an antiheating stabilizer such as2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl-acrylateand 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl-acrylate, a3,4-dihydro-2H-1-benzopurane type compound described in JP-A No.8-27508, a 3,3′-spyrodichroman type compound, a 1,1-spyroindan typecompound, morpholine, thiomorpholine, thiomorpholine oxide,thiomorpholine dioxide, a compound having piperazine skeleton as apartial structure thereof, and an oxygen scavenger such as adialkoxybenzene type compound described in Tokkai Hei 3-174150. A partof each of these antioxidants may be partially or regularly bonded witha polymer in a form of pendant. Moreover, the plasticizer may beincluded as a partial structure of an additive such as an antioxidant,an acid scavenger and a UV absorbent.

(Acid Scavenger)

As the acid scavenger, ones containing an acid capturing epoxy compounddescribed in U.S. Pat. No. 4,137,201 are preferable. Such the epoxycompounds as the acid scavenger have been known in the field of the art,and examples thereof include glycidyl ether of various polyethyleneglycols, particularly a polyglycol driven by condensation ofapproximately 8 to 40 moles of ethylene glycol per mole of thepolyglycol, diglycidyl ether of glycerol, an metal epoxy compound, forexample, ones usually used in a vinyl polymer composition, an epoxideether condensate, diglycidyl ether of bisphenol A namely4,4′-dihydroxydiphenyldimethylmthane, an epoxide unsaturated fatty acidester, particularly an ester of alkyl having 2 to 4 carbon atoms of afatty acid having 2 to 22 carbon atoms such as butyl epoxystearate, anda triglyceride of one of various epoxide long chain fatty acids, forexample, an epoxide soybean oil composition. The examples furtherinclude an epoxide of plant oil or another unsaturated natural oil. Theepoxide oils are sometimes called as epoxide of natural glyceride orepoxide of unsaturated fatty acid and these fatty acids are eachcontains 12 to 22 carbon atoms. An epoxy group-containing epoxide resincompound available on the market EPON815c, manufacture byMiller-Stephenson Chemical Co., Ltd., and an epoxide ether oligomercondensation product represented by Formula (2) are particularlypreferable.

In the above formula, n is an integer of 0-12. Further employable acidscavenger includes those described in Tokkai Hei 5-194788, paragraphs 87to 105.

(Photo-Stabilizer)

As the photo-stabilizer, a hindered amine photo-stabilizer (HALS) isemployable, which is known compound and includes a2,2,6,6-tetra-alkylpiperidine compound and its acid addition salt and ametal complex thereof, as described in U.S. Pat. No. 4,619,956, columns5 to 11 and U.S. Pat. No. 4,839,504, columns 3 to 5. Such the compoundsinclude a compound represented by Formula-(3).

In the above formula, R1 and R2 are each a hydrogen atom or asubstituent. Concrete examples of the hindered amine photo-stabilizerinclude 4-hydroxy-2,2,6,6-tetramethyl-piperidine, a allyl-4-hydroxy2,2,6,6-tetramethyl-piperidine,1-benzyl-4-hydroxy-2,2,6,6-tetramethyl-piperidine,1-(4-t-butyl-2-butenyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine,4-stearoyloxy-2,2,6,6-tetramethylpiperidine,1-ethyl-4-saliciloyloxy-2,2,6,6-tetramethylpiperidine,4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine,1,2,2,6,6-pentamethylpiperidine-4-yl-β(3,5-di-t-butyl-4-hydroxyphenyl)-propionate,1-benzyl-2,2,6,6-tetramethyl-4-piperidinylamleinate,(di-2,2,6,6-tetramethylpiperidine-4-yl)-adipate,(di-2,2,6,6-tetramethylpiperidine-4-yl)-sebacate,(di-1,2,3,6-tetramethyl-2,6-diethyl-piperidine-4-yl)-sebacate,(di-1-allyl-2,2,6,6-tetramethylpiperidine-4-yl)-phthalate,1-acetyl-2,2,6,6-tetramethylpiperidine-4-yl)-acetate, trimellitic acidester of tri-(2,2,6,-tetramethyl-piperidine-4-yl),1-acryloyl-4-benzyloxy-2,2,6,6-tetramthyl-piperidine,di-(1,2,2,6,6-pentamethyl-piperidine-4-yl) dibutylmalonate,di-(1,2,3,6-tetramethyl-2,6-diethylpiperidine-4-yl) dibenzylmlonate,dimethyl-bis-(2,2,6,6-tetramethylpieridine-4-oxy)-silane,tris-(1-propyl-2,2,6,6-tetramethylpieridine-4-yl) phosphite,tris-(1-propyl-2,2,6,6-tetramethylpieridine-4-yl) phosphate,N,N′-bis-(2,2,6,6-tetramethylpieridine-4-yl)-hexamethylene-1,6-di-acetoamide,1-acetyl-4-(N-cyclohexylacetamido)-2,2,6,6-tetramethylpieridine,4-benzylamino-2,2,6,6-tetramethyl-pieridine,N,N′-bis-(2,2,6,6-tetramethyl-pieridine-4-yl)-N,N′-dibutyl-adipamide,N,N′-bis-(2,2,6,6-tetramethylpieridine-4-yl)-N,N′-dicyclohexyl-(2-hydroxypropylene),N,N′-bis-(2,2,6,6-tetramethyl-pieridine-4-yl)-p-xylenediamine,4-(bis-2-hydroxyethyl)-amino-1,2,2,6,6-pentamethylpiperidine,4-methacrylamido-1,2,2,6,6-pentamethylpiperidine and methylα-cyano-β-methyl-β-[N-2,2,6,6-tetramethylpieridine-4-yl)]-amino-acrylate.Preferable hindered amine photo-stabilizer includes the following HALS-1and HALS-2.

These hindered amine photo-stabilizers may be employed solely or incombination of two or more kinds thereof. The hindered aminephoto-stabilizer may be employed together with the additives such as theplasticizer, acid scavenger and UV absorbent, and may be introduced intoa part of the structure of the additive. Though the adding amount of thephoto-stabilizer is suitably decided within the range in which theobject of the invention is not disturbed, and is preferably from 0.01 to10%, more preferably from 0.01 to 56, and particularly preferably from0.05 to 1%, by weight.

<Dye>

In order to optimize color of the cellulose ester film, dyes maypreferably be added. For example, a blue dye may be added to reduce ayellow hue of the film. Preferable are anthraquinone type dyes.

The anthraquinone type dye may have any of several kinds of substituentsin any of the 8 positions of anthraquinone. Preferable substituents arean aniline group, a hydroxyl group, an amino group, a nitro group and ahydrogen atom. Blue dyes disclosed in JP-A 2001-154017, paragraphnumbers [0034]-[0037], specifically, anthraquinone dyes, are preferablyadded to the film.

Additives described above may be added to a dope containing celluloseester via batch mixing, or, alternatively, they may be added via in-linemixing using a dissolving solvent of the additives. Specifically,microparticles are preferably added, partially or entirely via anin-line mixing, in order to reduce a load to a filter.

In an in-line mixing process of additive solutions, a smaller amount ofcellulose ester is preferably dissolved in the dope in order to obtain asufficiently mixed dope. The amount of cellulose ester is preferablyfrom 1 to 10 weight parts in 100 weight parts of solvent, and morepreferably from 3 to 5 weight parts.

As a mixer for in-line addition and mixing, for example, a static mixermanufactured by Toray Engineering Co., Ltd. or a static type in-linemixer High-Mixer SWJ manufactured by Toray Engineering Co., Ltd., ispreferably used.

<Manufacturing Method of Retardation Film>

The manufacturing method of the cellulose ester retardation film of thepresent invention will now be explained.

The manufacturing method of the retardation film of the presentinvention contains the processes of (i) a dope preparing process inwhich cellulose ester and an additive, for example, above mentionedplasticizer, are dissolved in a solvent, (ii) a flow-casting process inwhich a dope is flow-cast on a belt-like or a drum-like metal support,(iii) a drying process in which a flow-cast dope is dried to form a web,(iv) a peeling process in which a dried web is peeled from the metalsupport, (v) a stretching process, (vi) a further drying process, (Vii)a heat treatment process and (viii) a winding process of the cooledcellulose ester film. The retardation film of the present inventionpreferably contain 70-95% by weight of cellulose ester based on theweight of solid component of the retardation film.

The dope preparation process will now be explained. In the dopepreparation process, a higher content of cellulose ester in the dope ispreferable since duration of the drying process following theflow-casting process is shortened, however, a too high content mayresult in loss of filtration accuracy. Preferable content of celluloseester is from 10-35% by weight and more preferably from 15-25% byweight.

A solvent may be used alone, however, two or more solvents may also beused together. A mixture of a good solvent and a poor solvent is morepreferably used to increase manufacturing efficiency. A mixed solventbeing rich in a good solvent is preferable to increase solubility ofcellulose ester. The preferable mixing ratios are from 70 to 98 percentby weight of a good solvent, and from 2 to 30 percent of a poor solvent.Herein, a good solvent is described as being capable of dissolvingcellulose ester with a single use, and a poor solvent as being incapableof dissolving nor swelling cellulose ester alone. Sometimes, a solventworks as a good solvent of a cellulose ester, and sometimes as a poorsolvent depending on the average acylation degree (degree of acylsubstitution) of the cellulose ester. For example, acetone is a goodsolvent for an acetic ester of cellulose of which the acetylation degreeis 2.4, as well as for cellulose acetatepropionate, however, it is apoor solvent for cellulose acetate of which acetylation degree is 2.8.

Example of good solvents used in the present invention include: anorganic halide (such as methylene chloride), dioxolane, acetone, methylacetate and methyl acetoacetate, of these, methylene chloride and methylacetate are specifically preferable. However, the present invention isnot specifically limited thereto.

Examples of poor solvents used in the present invention include:methanol, ethanol, n-butanol, cyclohexane and cyclohexanone, however,the present invention is not specifically limited thereto. A dope maypreferably contain from 0.01 to 2 percent by weight of water.

In the process of preparing a dope, cellulose ester is dissolved using acommon method. Dissolving cellulose ester at a higher temperature ispossible when the heating is carried out under a higher pressure.Formation of a gel or an insoluble agglomerate (known as “Mamako” inJapanese which represents insoluble residue when powder is dissolved ina solvent) may be avoided when the dissolving temperature is higher thanthe ambient pressure boiling point of the mixed solvents, andsimultaneously the temperature is in the range where the mixed solventsdo not boil under the applied higher pressure. The following dissolvingmethod is also preferable, in which cellulose ester is swollen in amixture of good and poor solvents followed by adding good solvents todissolve the swollen cellulose ester.

Pressure may be applied by injecting an inert gas such as nitrogen or byincreasing the vapor pressure of the solvents by heating. Heating ispreferably carried out from the outside of the container. A jacket typeheater is preferable because the temperature is easily controlled.

A higher dissolving temperature is preferable with respect to thesolubility of the cellulose ester, however, too high a temperature maylower the productivity because the pressure also becomes very high. Thedissolving temperature is preferably 45-120° C., more preferably 60-110°C. and still more preferably 70-105° C. The pressure should becontrolled not to allow boiling at the set temperature.

A low temperature dissolution method is also preferably utilized, bywhich cellulose ester is successfully dissolved in solvents such asmethyl acetate.

In the next process, the cellulose ester solution thus prepared isfiltered using an appropriate filter material. A filter material with asmaller absolute filtration accuracy is more preferable for removinginsoluble materials, however, too small a filtration accuracy easilycause clogging up of the filter. The absolute filtration accuracy of thefilter is preferably not larger than 0.008 mm, more preferably0.001-0.008 mm and still more preferably 0.003-0.006 mm.

The filter material used in the present invention is not specificallylimited, and plastic filters (such as polypropylene and Teflon®) as wellas metal(alloy) filters (such as stainless steel) are preferable, sincethese materials are free from peeling of a fiber, which may occur whenfibrous material is used. Impurities and, specifically, luminescentforeign materials contained in the cellulose ester are preferablydiminished or entirely removed by filtering.

“Luminescent foreign materials” denote impurities which are observed asbright spots when a cellulose ester film is placed between twopolarizing plates arranged in a crossed Nicols state, illuminated with alight from one side and observed from the other side. The number ofluminescent foreign materials of larger than 0.01 mm in diameter ispreferably less than 200 per cm², more preferably less than 100 per cm²and still more preferably from 0 to 10 per cm². The number ofluminescent foreign materials of less than 0.01 mm in diameter ispreferably minimal.

The dope may be filtered by any common method. One of these preferablefiltering methods is to filter the dope at temperatures which are higherthan the ambient pressure boiling point of the mixed solvents, andsimultaneously in the range where the mixed solvents do not boil under ahigher pressure. This method is preferable because the pressuredifference between before and after filtering is reduced. The filteringtemperature is preferably from 45 to 120° C., more preferably from 45 to70° C. and still more preferably from 45 to 55° C.

The pressure applied during filtering is preferably low, beingpreferably less than 1.6 MPa, more preferably less than 1.2 MPa andstill more preferably less than 1.0 MPa.

Flow-casting of a dope will be explained below:

A metal support polished to a mirror finished surface is used in theflow-casting process. A polished stainless steel belt or a plated castdrum is used as a metal support. The width of the support is preferablyfrom 1 to 4 m. The surface temperature of the metal support ispreferably from −50° C. to a temperature just below the boiling point ofthe solvent. A relatively high temperature of the support is morepreferable because the web is more quickly dried, however, too high atemperature may cause foaming or loss of flatness of the web. Thetemperature of the support is appropriately determined in the range of0-100° C., however, preferably 5-30° C. Another preferable method isthat a web is gelated by cooling the drum followed by peeling the webfrom the drum while the web still contains much solvent. The method tocontrol the temperature of the support is not specifically limited and amethod of blowing warm or cool air onto the support or to apply warmwater on the rear side of the support is acceptable. The warm watermethod is more preferable because the temperature of the metal supportbecomes stable in a shorter time due to more efficient thermalconduction. In the case when warm air is used, in order to avoid thelowering of the web temperature due to latent heat of evaporation, theair temperature should be higher than the desired temperature of thesupport while avoiding foaming of the web. Drying process of the web ispreferably carried out effectively by changing the temperatures of thewarm air and the support during the process between flow-casting andpeeling.

In order to obtain a cellulose ester film with a sufficient flatness,the residual solvent content of the web when it is peeled from a metalsupport is preferably 10-150% by weight, however, it is more preferably20-40% by weight or 60-130% by weight. The residual solvent content isspecifically more preferably 20-30% by weight or 60-130% by weight.

The residual solvent content of the web is defined by the followingformula:Residual solvent content (% by weight)={(M−N)/N}×100where M represents the weight of a sample of the web collected in themanufacturing process or after manufacturing, and N represents theweight of the same sample after it was dried at 115° C. for 1 hour.

In the drying process of a cellulose ester film, the film is peeled fromthe support and further dried until the residual solvent decreases belownot more than 0.5%.

The peeled web is generally dried by a roll drying method (the web ispassed through many rolls alternately provided up and down in astaggered array), or by a tenter method in which both edges of the webare clipped while the web is being transported.

The web may be stretched in the film transportation direction by apeeling tension or by a transporting tension when or after the web ispeeled from the support. The web is preferably peeled from the supportwith a tension of 210 N/m or more and more preferably with a tensionfrom 220 to 300 N/m in order to stretch the film in the filmtransportation direction just after peeling.

An example of the stretching process (also referred to as the tenterprocess) of the present invention will now be explained using FIG. 2.

Process A of FIG. 2 is the process where a web conveyed from the peelingand transporting process (not illustrated, hereafter referred to asProcess D0) is held by clipping both edges. In Process B, the film isstretched in the lateral direction (perpendicular to the filmtransportation direction) with the stretching angle illustrated inFIG. 1. In Process C, stretching is completed and the film istransported to the next production process while being clipped.

A slitter which trims both edges of the film is preferably provided atany position between just after the web is peeled and just after.Process B or C. Specifically preferably, a slitter is provided justbefore Process A. When a stretching was carried out under the samecondition, a stretched film which is slit before Process B showed animproved orientation angle distribution of slow axes than a stretchedfilm without slitting.

This may be because an undesirable stretching in the film transportationdirection is suppressed between the peeling process and Process B wherethe film still contains much solvent.

In the tenter process, a different temperature domain may be purposelyprovided in the film to improve the orientation angle distribution. Alsoa neutral domain is preferably provided between two differenttemperature domains to prevent interference.

The stretching process may be divided into several steps. Biaxialstretching in both film transportation direction and the lateraldirection is also preferable. Biaxial stretching may be carried outsimultaneously or in series of steps. In stepped stretching, stretchingmay be carried out alternately in different directions or stepwise inone direction. Stretching alternately in different directions may alsobe added to the sequence of stepped stretching in one direction. Namely,the following stretching steps are also employable.

(i) Stretching in the film transportation direction followed bysimultaneously stretching in the lateral diretion and in the filmtransportation direction; and

(ii) Stretching in the film transportation direction followed bystretching in the lateral direction while the film is shrunk in the filmtransportation direction.

It is specifically preferable that the peeled web is stretched in thefilm transportation direction while the web still contains much residualsolvent, followed by stretching the web in the lateral direction byholding both edges of the web using pins or clips in the tenter processwhereby, a prescribed retardation value is provided to the web. Also, itis deduced that this process enables control of the free volume radius.The stretching may be carried out only in the lateral direction orsimultaneously in the lateral direction and the film transportingdirection (biaxial stretching). The stretching ratio of the web in boththe directions is preferably 1.05-2 and more preferably 1.15-1.5. Theweb may be shrunk in the film transportation direction when it isstretched in the lateral direction, where the stretching ratio ispreferably 0.8-0.99 and more preferably, 0.9-0.99. The enlarging ratioof the area of the web after stretching (or shrinking) in the lateraldirection and in the film transportation direction is preferably1.12-1.44 and more preferably 1.15-1.32. The enlarging ratio of the areaof the web is obtained by (stretching ratio in the lateraldirection)×(stretching ratio in the film transportation direction).

The term “stretching direction” used in the present invention usuallyrepresents the direction in which stretching tension is applied,however, when a web is biaxially stretched in a plurality of steps, the“stretching direction” may mean the direction in which the finalstretching ratio of the web becomes larger (which is usually the slowaxis direction) than the stretching ratio in the direction perpendicularto the above mentioned direction.

It is well known that, when a web is stretched in the lateral directionof the web, the dispersion of orientations of slow axes (hereafterreferred to as a orientation angle dispersion) becomes larger. In orderto conduct stretching in the lateral direction of a web while the ratioof Rt to Ro is kept constant and the orientation angle dispersion iskept small, relationships among web temperatures of processes A, B and Cexist, namely, the following relationships are preferably satisfied:Ta≦(Tb−10), or Tc≦Tb, and more preferably the both relationships aresimultaneously satisfied: Ta≦(Tb−10) and Tc≦Tb, wherein Ta, Tb and Tcrepresents temperatures in Celsius at each end of Processes A, B and C,respectively.

In order to decrease the above mentioned orientation angle dispersion,the temperature increasing rate of the web in Process B is preferably0.5-10° C./s.

The stretching duration in Process B is preferably shorter, however, alower limitation of the stretching duration may be prescribed tomaintain uniformity of the web. The temperature of Process B ispreferably 40-180° C., and more preferably 100-160° C.

In the tenter process, the coefficient of heat transfer may be constantor may be changed. The heat transfer coefficient is preferably in therange of 41.9×10³-419×10³ J/m²h, more preferably 41.9×10³-209.5×10³J/m²h, and further more preferably 41.9×10³-126×10³ J/m² hr.

The stretching rate in the lateral direction in Process B may beconstant or may be changed. The stretching rate is preferably in therange of 50-500%/minute, more preferably 100-400%/minute, and mostpreferably 200-300%/minute.

In the tenter process, the distribution of environmental temperature inthe lateral direction of the web is preferably smaller to improveuniformity of a web. The distribution of environmental temperature inthe lateral direction in the tenter process is preferably within ±5° C.,more preferably within ±2° C., and most preferably within ±1° C. Bydecreasing the distribution of environmental temperature, thetemperature distribution in the lateral direction of a web may also bedecreased.

In Process C, the width of a web held by a tenter is preferably reduced.Specifically, the width is preferably reduced to 95 to 99.5% of thewidth in the former process.

After a web is treated in the tenter process, a subsequent-dryingprocess (hereafter referred to as Process D1) is preferably provided.The web is preferably subjected to a heat treatment in the temperaturerange of 50 to 160° C., more preferably, 80 to 140° C., and mostpreferably 110 to 130° C.

In Process D1, the distribution of environmental temperature in thelateral direction of the web is preferably smaller to improve uniformityof the web. The distribution of environmental temperature in the lateraldirection is preferably within ±5° C., more preferably within ±2° C.,and most preferably within ±1° C.

Although the tension applied to the web while the film is beingtransported is affected by several factors, for example: the property ofa dope, the amount of residual solvent at the peeling process andProcess D0, and the temperature of Process D1, the film tension ispreferably 120-200 N/m, more preferably 140-200 N/m, and most preferably140-160 N/m.

In order to reduce further stretching in the film transportationdirection of the film in Process D1, a tension cut roll (an additionalroll which reduces the tension of the film while the film is conveyed)is preferably provided.

The means to dry the web is not specifically limited, and, for example,heated air, IR rays, a heated roll and microwave are applicable. Withrespect to the easiness, heated air is preferable.

The drying temperature in the drying process is preferably increasedstepwise in the range of 30-160° C.

In the present invention, the free volume and the free volume parameterare controlled in prescribed ranges by heat treating the web asdescribed above after the drying process of the web.

In the production process of the retardation film of the presentinvention, the retardation film is preferably subjected to a presstreatment with a pressure of 0.5-10 kPa in the thickness direction inthe heat treatment process after the drying process. The retardationfilm is preferably pressed uniformly using, for example nip rolls. Whenthe retardation film is pressed in the thickness direction, the web ispreferably thoroughly dried. The free volume and the free volumeparameter are controlled by applying pressure of 0.5-10 kPa from bothupside and downside of the retardation film. Specifically, two nip rollsarranged in parallel are used, or rolls such as calendar rolls may beused. The temperature in the press treatment is preferably 105-150° C.

Preferably conducted is the trimming of both edges of the film using aslitter after the drying is completed and before winding in a roll, toobtain a roll of the preferable shape. Further, both the edges of theretardation film is preferably subjected to a knurling treatment.

Knurling processing is carried out by pressing a heated emboss roll.Since the emboss roll has a fine convexo-concave surface, by pressingthis on the edges of the retardation film, a film having slightly bulkyedges.

The depth of the knurling treatment on both the edges of the retardationfilm are preferably 4-20 μm and the width of the knurling treatment ispreferably 5-20 mm.

The knurling processing is preferably provided after the drying processand before the film winding process.

A multilayer retardation film formed by a co-casting method using aplurality of dope solutions is also preferable. The multilayerretardation film can also have a layer containing a plasticizer. Thelayer containing a plasticizer may be a core layer, a skin layer or boththe layers.

The center-line surface roughness (Ra) of the surface of the retardationfilm of the present invention is preferably 0.001-1 μm.

In the present invention, the retardation film preferably has the Rovalue of 30-300 nm under a condition of 23° C. and 55% RH and the Rtvalue of 70-40 under the same condition, the Ro and Rt values beingdefined by the following formulas.Ro=(nx−ny)×dRt=(((nx+ny)/2)−nz)×dwherein Ro represents an in-plane retardation value; Rt represents anout-of-plane retardation value in a thickness direction; nx representsan in-plane refractive index in a slow axis direction; ny represents anin-plane refractive index in a fast axis direction; nz represents anout-of-plane refractive index in the thickness direction; and drepresents a thickness (nm) of the retardation film.

The retardation values Ro, Rt and an angle between the lateral directionof the long sheet film and the slow axis direction θ0 (°) were measuredby using an automatic birefringence meter: KOBRA-21ADH (manufactured byOji Keisokukiki Co., Ltd.) under a condition of 23° C. and 55% RH at awavelength of 590 nm.

The polarization degree p of the retardation film of the presentinvention is preferably 0.9990 or more, more preferably 0.9999 or more,still more preferably 0.99995 or more and specifically more preferably0.99999 or more. The polarization degree p is determined according tothe following equation.p=1−sin²(2θ1)·sin²(πRo/λ)wherein λ represents a wavelength of 590 nm at which measurement iscarried out. θ1 (radian) was converted from θ0 (°).

In order to achieve one of the objects of the present invention, theretardation film to be used for the polarizing plate of the presentinvention is preferably a film having a thickness of 30-150 μm producedby a casting method with respect to physical strength and productivityof the film. The film thickness is more preferably 40-120 μm.

(Measurement of Transmittance)

Transmittance T was measured as follows: Spectroscopic transmittanceτ(λ) was obtained, first, by measuring the transmittance of each sampleat wavelengths of every 10 nm in the range of 350-700 nm using aspectrophotometer U-3400 produced by Hitachi Ltd. From the obtainedspectroscopic transmittance, transmittances at wavelengths of 380, 400and 500 nm were evaluated.

The haze of each samples was determined as follows. The haze of theretardation film used in the present invention is preferably less than1% and more preferably in the range of 0-0.1%.

(Haze Value)

A haze value was determined according to the method of JIS K-6714 usinga haze meter (1001DP produced by Nippon Denshoku). The haze value may beused as an index of transparency.

<Antiblocking Layer>

The retardation film of the present invention preferably has anantiblocking layer. An antiblocking layer is formed by coating a layercontaining microparticles on the surface of a film and the layerexhibits a minute convex on the surface, which provides a slipperysurface. The shape of microparticle is not specifically limited and anyshape of microparticles are usable, for example, spherical shape, lodshape, plate-like shape and discotic shape.

Examples of inorganic microparticles include: a metal oxide, a metalhydroxide, a silicate, a carbonate, and a phosphate. Specific examplesthereof include: silicon dioxide, titanium dioxide, aluminum oxide,zirconium oxide, calcium carbonate, talc, clay, calcinated caolin,calcinated calcium silicate, tin oxide, indium oxide, zinc oxide, ITO,hydrated calcium silicate, aluminium silicate, magnesium silicate, andcalcium phosphate. Microparticles containing silicon is preferable andsilicon dioxide is specifically preferable.

These microparticles are available on the marketed with the productnames of Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50 andTT600 (produced by Nippon Aerosil Co., Ltd.), and can be used, forexample. Microparticless of zirconium oxide are also available on themarket with the product names of Aerosil R976 and R811 (produced byNippon Aerosil Co., Ltd.). The particles of zirconium oxide are alsoavailable on the marketed with the product names of aerosils R976 andR811 (produced by Nippon Aerosil Co., Ltd.). Alternatively, examples ofpolymer microparticles include: silicone resin microparticles,fluororesin microparticles, and acryl resin microparticles. Of these,silicone resin microparticles, especially three dimensionally networkedsilicone resin microparticles are preferably used. Examples of silicone:resin microparticles include: TOSPERL 103, 105, 108, 120, 145, 3120 and240, which are manufactured by Toshiba Silicone Co., Ltd.

Of these, Aerosil 200V and Aerosil R972V are specifically preferable,since a higher antiblocking property is obtained while keeping a lowhaze value. The dynamic friction coefficient is preferably reduced to0.9 or less and more preferably in the range of 0.1-0.9 by using theseantiblocking agents.

The content of microparticles contained in an antiblocking layer ispreferably 0.1-50% by weight and more preferably 0.1-10% by weight basedon the weight of the binder. The increase in a haze value afterproviding an antiblocking layer is preferably not more than 1%, morepreferably not more than 0.5% and specifically preferably in the rangeof 0-0.1.

Specifically, an antiblocking layer is formed by coationg a compositioncontaining a solvent which dissolves or swells the cellulose ester film.As the solvent, in addition to the mixture of a solvent which dissolvesthe cellulose ester and a solvent which swells the cellulose ester, asolvent which does not dissolve the cellulose ester may also be added.The mixing ratio of these solvents and the amount of applied coatingcomposition are determined depending on the kind of the resin or degreeof the curl of the film. The retardation film of the present inventionis favorable because variations in retardation values are suppressed bycoating the composition described above.

When the curl of the retardation film is controlled by applying theantiblocking layer, a curl toward the antiblocking layer side surface ofthe retardation film is effectively caused by increasing the amount of asolvent which dissolves or swells the cellulose ester while decreasingthe amount of a solvent which does not dissolve the cellulose ester. Themixing ratio is preferably as follows: (a solvent which dissolves orswells the cellulose ester): (a solvent which does not dissolve thecellulose ester)=10:0-1:9. Examples of a solvent which dissolves orswells a transparent resin film include: dioxane, acetone, methylethylketone, N,N-dimethylformamide, methyl acetate, ethylacetate,trichloroethylene, methylene chloride, ethylene chloride,tetrachloroethane, trichloroethane and chloroform. Examples of a solventwhich does not dissolve a transparent resin film include: methanol,ethanol, n-propyl alcohol, i-propyl alcohol, n-butanol, cyclohexanol,and hydrocarbons (such as toluene and xylene).

These coating compositions are applied on a transparent resin filmpreferably in a wet thickness of 1-0.100 μm or specifically preferably5-30 μm by using a gravure coater, a dip coater, a reverse coater, awire bar coater, a die coater, a spray coater or an ink-jet printing.Examples of a binder resin of an antiblocking layer include: vinylpolymers and copolymers, such as, vinyl chloride-vinyl acetatecopolymer, a polyvinyl chloride resin, a vinyl acetate resin, vinylacetate-vinyl alcohol copolymer, partially hydrolyzed vinylchloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloridecopolymer, vinyl chloride-acrylonitrile copolymer, ethylene-vinylalcohol copolymer, chlorinated polyvinyl chloride, ethylene-vinylchloride copolymer and ethylene-vinyl acetate copolymer; cellulosederivatives, such as, nitrocellulose, cellulose acetate propionate(preferably the acetylation degrees of 1.8-2.3, the propionylsubstitution degree of 0.1-1.0), diacetyl cellulose andcellulose-acetate-butylate; rubber resins, such as, maleic acid-acrylicacid copolymer, acrylic ester copolymer, acrylonitrile-styrenecopolymer, chlorinated polyethylene, acrylonirile-chlorinatedpolyethylene-styrene copolymer, methylmethacrylate-Butadiene-styrenecopolymer, an acryl resin, a polyvinyl acetal resin, a polyvinyl butyralresin, a polyester polyurethane resin, a polyether polyurethane resin, apolycarbonate polyurethane resin, a polyester resin, a polyether resin,a polyamide resin, an amino resin, a styrene-butadiene resin, and abutadiene-acrylonirile resin; silicone resins; and fluorine resins.Varieties of homopolymers and copolymers originated from acryl ormetacryl monomers are available on the market and a preferable materialcan be selected from these, for example: Acrypet MD, VH, MF and V(produced by Mitsubishi Rayon Co., Ltd.), Hi Pearl M-4003, M-4005,M-4006, M-4202, M-5000, M-5001 and M-4501 (produced by Negami ChemicalIndustrial Co., Ltd.), Dianal BR-50, BR-52, BR-53, BR-60, BR-64, BR-73,BR-75, BR-77, BR-79, BR-80, BR-82, BR-83, BR-85, BR-87, BR-88, BR-90,BR-93, BR-95, BR-100, BR-101, BR-102, BR-105, BR-106, BR-107, BR-108,BR-112, BR-113, BR-115, BR-116, BR-117 and BR-118 (produced byMitsubishi Rayon Co., Ltd.)

Specifically preferable are cellulose resins, for example, diacetylcellulose and cellulose acetate propionate.

An anti blocking layer enables maintaining the flatness of a retardationfilm, and reducing the variations in retardation values.

<Polarizing Plate>

The polarizing plates of the present invention will now be described.

It is possible to prepare the polarizing plates employing commonmethods. It is preferable that the retardation film of the presentinvention is subjected to an alkali saponification treatment and theresulting retardation film is adhered, employing an aqueous solution ofcompletely-saponified polyvinyl alcohol, to at least one surface of apolarizing film which has been prepared by being immersed into an iodinesolution and subsequently being stretched. The retardation film of thepresent invention may also be used for the reverse surface of thepolarizing film or other polarizing plate protective film may be usedfor the reverse surface. Employed as a polarizing plate protective filmon the other surface, instead of the retardation film of the presentinvention, may be commercially available retardation films. For example,preferably employed as commercially available retardation films areKC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3 and KC8UCR-4 (allproduced by Konica Minolta Opt, Inc.). Alternatively, it is alsopreferable to use a polarizing plate protective film having a functionof an optical compensating film by containing an optical anisotropiclayer, which is prepared by orienting liquid crystal compounds such as adiscotic liquid crystal, a rod-shaped liquid crystal, or a cholestericliquid crystal. It is possible to form the optical anisotropic layeremploying the method described in JP-A No. 2003-98348. By employing thecombination of an antireflection film, it is possible to obtainpolarizing plates which exhibit excellent flatness and viewing angleincreasing effects.

The polarizing film which is a major constituting component ofpolarizing plates, as described herein, refers to the element which onlytransmits the light of a polarized wave in the definite direction. Oneof the typical polarizing film, which is presently known, is a polyvinylalcohol based polarizing film which is classified to one prepared bydying polyvinyl alcohol based film with iodine and the other prepared bydying the same with dichroic dyes. The polarizing film is prepared insuch a manner that an aqueous polyvinyl alcohol solution is cast and theresulting cast film is subjected to uniaxial orientation and dying, oris subjected to dying and uniaxial orientation and subsequently to adurability treatment employing preferably boron compounds. One surfaceof the retardation film of the present invention is adhered to thesurface of the above polarizing film, whereby a polarizing plate isformed. Adhesion is performed employing preferably water based adhesivescontaining completely-saponified polyvinyl alcohol as a major component.

A polarizing film is subjected to uniaxial orientation (commonly in thelongitudinal direction). When a polarizing plate is allowed to stand athigh temperature and high humidity, the length in the orientationdirection (commonly in the longitudinal direction) decreases, while thelength in the perpendicular direction (commonly the width direction)increases. As the thickness of a polarizing plate protective filmdecreases, shrinkage ratio increases, specifically, shrinkage ratio inthe longitudinal direction increases. Generally, a polarizing film isadhered to a polarizing plate protective film so that the stretchingdirection of the polarizing film lies in the casting direction (alsoreferred to as the MD direction (machine direction) or the filmtransportation direction) of the polarizing plate protective film.Consequently, it is important that when the thickness of the polarizingplate protective film is decreased, elongation and shrinkage ratio inthe casting direction of the polarizing film is preferably decreased.The retardation film of the present invention is suitably applied tosuch a polarizing plate protective film due to its excellent dimensionalstability.

Namely, in a durability test of the retardation film of the presentinvention under the condition of 60° C.; 90% RH, wavy unevenness of thefilm does not appear. Also a polarizing plate having a retardation filmof the present invention on the rear surface exhibits a wide viewingangle even after the durability test resulting in providing an excellentvisibility.

It is also possible to constitute a polarizing plate by adhering aprotective film on one surface of the polarizing plate and a separatefilm on the reverse surface. The protective film and the separate filmare employed to protect the polarizing plate at its shipping and productinspection. In this case, the protective film is adhered to protect thesurface of the polarizing plate on the surface reverse to the surfacewhich is adhered to a liquid crystal cell. On the other hand, theseparate film is employed to cover the adhesion layer to adhere to theliquid crystal cell and is provided on the surface to adhere thepolarizing plate to a liquid cell.

In the conventional polarizing plate producing process, the retardationvalues may have changed for each production line. Although the reason isnot specified, it seems that a configuration of the rolls in atransportation process or a film transportation condition affect theretardation values. Moreover, even in the same line, changes of settingor changes with the lapse of time in, for example, saponificationtemperature and duration, alkali concentration, pH, drying temperature,adhering velocity, film tension in the transportation process andadhering pressure of the films may have affected the retardation values.Basically, these conditions should not be changed, however, when foam inthe dope, machine trouble or wrinkles on the film are found, change inline speed and other slight changes in various conditions accompanyingthe change in line speed are occasionally carried out. Alternately, whenthe polarizing plate protective film provided on the reverse surface ofa polarizing plate is changed, the above conditions may also be changed.Further, when the production lined is stopped due to a trouble of somekind and then started again, it takes much time until the stableproduction is recovered. So far, the retardation values of theretardation film tends to have been affected by the above mentionedslight changes in setting, anti-trouble measures and changes due to thelapse of time, however, by employing the retardation film of the presentinvention, a polarizing plate exhibiting a smaller variation inretardation values in spite of the changes in the production conditionhas been obtained. Using this polarizing plate, an LCD exhibiting a highdisplay quality has been obtained. Specifically, even in LCDs using aLED direct illumination backlight unit provided behind the liquidcrystal cell, LCDs uniform in quality, exhibiting high front contrast ofthe display and a small variation in contrast, have been obtained.

<Display>

By using the polarizing plate of the present invention, a variety ofdisplays excellent in visibility are provided. The cellulose ester filmof the present invention is usable for the liquid crystal displays ofvarious drive modes, such as STN, TN, OCB, HAN, VA (MVA, PVA), and IPS.Of these, preferable is an application of the polarizing plate of thepresent invention to an VA (MVA, PVA) mode LCD, by which an LCD of 30inch size or more exhibiting reduced environmental variation of thequality and reduced leakage of light in the peripheral area of thedisplay has been obtained. Specifically, an LCD employing a retardationfilm of the present invention exhibited reduced environmental variationof the quality and reduced leakage of light in the peripheral area ofthe display. Also, reducing effects for color unevenness, wavy surfaceand eye fatigue after a long viewing were obtained.

Although the backlight unit used for the liquid crystal display usingthe polarizing plate of the present invention may be a sidelight type, adirect illumination type or a combination of both types, preferable is adirect illumination backlight unit provided behind a liquid crystalcell.

A specifically preferable backlight unit include a LED directilluminating backlight unit for a color LCD provided behind a liquidcrystal cell containing Red(R) LEDs, Green(G) LEDs and Blue(B) LEDs, ofwhich peak wavelengths are, for example, 610 nm or more for Red(R),530±10 nm for Green(G), and 480 nm or less for Blue(B). Examples ofGreen(G) LED having a peak wavelength in the above range include DG112H(made by Stanley Electric Co., Ltd.), UG1112H (made by Stanley ElectricCo., Ltd.), E1L51-3G (made by TOYODA GOSEI CO., LTD.), E1L49-3G (made byTOYODA GOSEI CO., LTD.), NSPG500S (made by Nichia Corp.). Examples ofRed (D) LED include FR1112H (made by Stanley Electric Co., Ltd.),FR5366X (made by Stanley Electric Co., Ltd.), NSTM515AS (made by NichiaCorp.), GL3ZR2D1COS (product made from Sharp) and GM1JJ35200AE (productmade from Sharp).

Examples of Blue (B) LED include DB1112H (made by Stanley Electric Co.,Ltd.), DB5306X (made by Stanley Electric Co., Ltd.), E1L51-3B (made byTOYODA GOSEI CO., LTD.), E1L4E-SB1A (made by TOYODA GOSEI CO., LTD.),NSPB630S (made by Nichia Corp.) and NSPB310A (made by Nichia Corp.).

LEDs of the above three colors may be combined to make a backlight unitor a white LED may be used. Also, direct illumination backlight unitsare disclosed in, for example, JP-A No. 2001-281656, JP-A No.2001-305535 in which dot type LED light source is used, and JP-A No.2002-311412, however, backlight units are not limited thereto.

EXAMPLES

The present invention will now be specifically explained using examples,however, the present invention is not limited thereto.

<Preparation of Dope>

The following material were loaded in turn and sealed in a container andthe temperature was raised from 20° C. to 80° C. The loaded materialswere stirred in the container at 80° C. for three hours, whereby thecellulose ester was completely dissolved. Then, stirring was stopped andthe temperature was lowered to 43° C. Obtained solution was filteredusing Filter Paper No. 244 produced by Azumi Filter Paper Co., Ltd toobtain Dope A.

(Preparation of Dope A) Cellulose ester (cellulose acetate propionate;the 100 weight parts  acetylation degree of 1.9, propionyl substitutiondegree of substitution 0.8) Trimethylolpropane tribenzoate  5 weightparts Ethylphthalylethyl glycolate  5 weight parts Silica particles(Aerosil R972V produced by Nippon 0.1 weight parts  Aerosil Co., Ltd.)Methylene chloride 300 weight parts  Ethanol 40 weight parts(Preparation of Dope B)

Dope B was prepared in the same manner as Dope A except that thematerials were changed as follows: Cellulose ester (acetylation degreeof 2.7) 100 weight parts  Triphenyl phosphate 10 weight partsBiphenyldiphenyl phosphate  2 weight parts Silica particles (AerosilR972V produced by Nippon 0.1 weight parts  Aerosil Co., Ltd.) Methylacetate 260 weight parts  Ethanol 80 weight parts

The dope prepared as above was cast through a casting die kept at 30° C.on a stainless steel endless support kept at 30° C. After the formed webwas dried until the amount of residual solvent decreased to 80% byweight, the web was peeled from the support using a peeling roller.

Subsequently, the web was dried in an 70° C. air flow by passing throughmany rollers placed alternatively up and down in a staggered manner (thetransport-drying process), then the both edges of the web were clippedwith a tenter and stretched by 1.3 times in the lateral direction at120° C.

The stretched web was further dried in an 105° C. air flow by passingthrough many rollers placed alternatively up and down in a staggeredmanner to obtain a film containing residual solvent of 0.3% by weight.The obtained film was heat treated for 15 minutes under a condition ofprescribed temperature and rate of atmosphere replacement, then, cooledto ambient temperature and wound in a roller to obtain 20 rolls of longsheet Retardation Film 1 (cellulose ester film) having the followingfeatures: thickness of 80 μm, length of 1000 m, in-plane retardationvalue of Ro=50 (nm) and retardation value in the thickness direction ofRt=130 (nm) (the retardation values were measured at 23° C. under 55% RHat a wavelength of 590 nm).

Retardation Films 2-22 were prepared in the same manner as RetardationFilm 1 except that the heat treatment temperature and the rate ofatmosphere replacement were changed as shown in Table 1. For each ofRetardation Films 4, 5, 7, 8, 10, 12, 19 and 20, a prescribed pressurewas applied in the thickness direction of the film using niprollersarranged in many steps in the heat treatment process.

The rate of atmosphere replacement is the number of times replacing theatmosphere of a heat treatment chamber by fresh-air per unit time,provided that the volume of the heat treatment chamber is expressed as V(m³) and the amount of fresh-air sent to the heat treatment chamber isexpressed as FA (m³/h).

Rate of atmosphere replacement=FA/V (times/h) Polarizing plates wereprepared by providing one of the obtained retardation films on onesurface of each polarizing plate as a protective film and providingPolarizing Plate Protective Film C on the reverse surface. ProtectiveFilm C will be described below.

<Polarizing Plate Protective Film C> (Silica Dispersed Diluting SolutionC) Aerosil 972V (produced by NIPPON AEROSIL Co., 12 weight parts Ltd.)(Mean primary particles diameter of 16 nm, apparent specific gravity of90 g/l) Ethanol 88 weight parts

The above materials were mixed and stirred for 30 minutes using adissolver, followed by dispersing with Manton-Gaulin homogenizer. Theresulting solution was mixed with 88 weight parts of methylene chloridewhile stirring and further dispersed for 30 minutes using a dissolver toobtain Silica Dispersed Diluting Solution C.

(Preparation of In-Line Additive Solution C) TINUVIN 109 (produced byCiba Specialty Chemicals 11 weight parts Inc.) TINUVIN 171 (produced byCiba Specialty Chemicals  5 weight parts Inc.) Methylene chloride 100weight parts 

The above materials were loaded in a sealed reaction vessel and welldissolved by heating and stirring, followed by filtering.

In the resulting solution, 36 weight parts of Silica Dispersed DilutingSolution C was added while the solution was being stirred and stirredfor 30 minutes. Further, 6 weight parts of cellulose acetate propionate(acetyl substitution degree of 1.9, propionyl substitution degree of0.8) was added while stirring and further stirred for 60 minutes. Theresulting solution was filtered with polypropylen wound cartridge filterTCW-PPS-1N produced by Advantec Toyo, Ltd. to prepare In-Line AdditiveSolution C.

(Preparation of Dope C) Cellulose ester (cellulose triacetate preparedfrom 100 weight parts cotton linter: Mn = 148000, Mw = 310000, Mw/Mn =2.1, acetylation degree: 2.92) Trimethylolpropane tribenzoate  5 weightparts Ethylphthalylethyl glycolate  5 weight parts Methylene chloride440 weight parts Ethanol  40 weight parts

The above materials were loaded in a sealed reaction vessel and welldissolved by heating and stirring, and filtered using Filter paper No.24 produced by Azumi Filter Paper Co., Ltd. to obtain Dope C. Dope C wasfurther filtered in a film forming line using Finemet NF produced byNippon Seisen Co., Ltd. Also, In-Line Additive Solution C was filteredin an in-line additive solution line using Finemet NF produced by NipponSeisen Co., Ltd. 100 weight parts of filtered Dope C was mixed with 2weight parts of filtered In-Line Additive Solution C and throughly mixedusing a in-line mixer (Hi-Mixer SWJ produced by Toray Engineering Co.,Ltd.), and uniformly cast on a stainless steel belt support of a widthof 1800 mm at 35° C. using a belt casting apparatus. The cast film wasdried until the residual solvent decreased to 120% on the belt supportand peeled from the belt support. The peeled cellulose ester web wasfurther dried at 35° C. and slit into a width of 1650 mm, then, furtherdried at 135° C. while the web was stretched by 1.1 times using atenter. The amount of the residual solvent when the tenter stretchingwas started was 30%.

The drying process was finalized by passing the web through many rollsat 110° C. and 120° C. The web was then slit into a width of 1.4 m andboth the edges of widths of 15 mm were subjected to a 10 μm depth ofknurling treatment. The web was wound to a core of 6 in. in diameterwith initial tension of 220 N/m and final tension of 110 N/m. ThusPolarizing Plate Protective Film C was obtained. The stretchingmagnification in the film transporting direction of the web just afterthe web was peeled from the belt support was 1.07, which was estimatedfrom the velocity of the stainless steel belt support and the drivingvelocity of the tenter. The amount of residual solvent of obtainedPolarizing Plate Protective Film C was 0.3%, the average thickness was80 μm and the length was 1000 m.

<Saponification of Retardation Films>

Each of the 20 rolls of each of Rtardation Films 1-22 was subjected to asaponification treatment described below by transporting the film usingrollers.

<Alkali Saponification Treatment>

Saponification process: in 2M-NaOH at 50±3° C. for 1.5 minutes;

Washing process: in water at 30±3° C. for 1 minute;

Neutralization process: in 10 wt % HCl at 30±3° C. for 1 minute; and

Washing process: in water at 30±3° C. for 1 minute

The saponification process was followed by the washing process, theneutralization process, the further washing process and, finally, adrying process at 96° C.

The head portion and the tail portion of each of the 20 long sheet rollswere sampled before and after the saponification treatment to obtain intotal 40 specimens for each of Retardation Films 1-22 before and afterthe saponification treatment. The measurement of retardation values werecarried out for each specimen and, by averaging the 40 data, thedifference in each retardation value before and after the saponificationtreatment and the fluctuation of each retardation value over the 40specimens after the saponification treatment. The same measurement wasrepeated for each of Retardation films 1-22. When the variation in eachretardation value after the saponification treatment is not more than±3%, the retardation film is suitable for practical use.

Retardation values Ro and Rt were measured by using an automaticbirefringence meter: KOBRA-21ADH (manufactured by Oji Keisokukiki Co.,Ltd.) at 23° C. under 55% RH, at a wavelength of 590 nm.

(Preparation of Polarizing Plate).

Subsequently, each of the above 40 retardation plates and saponifiedPolarizing Plate Protective Film C were adhered on both surfaces of apolarizing film prepared by the method described below to obtain 40polarizing plates.

Process 1: Saponifying each of the retardation films and PolarizingPlate Protective Film C according to the method described above.

Process 2: Immersing the following polarizing film for 1-2 seconds intoa solution containing polyvinyl-alcohol adhesive agent of which solidcontent is 2 wt % by weight.

Process 3: Removing the excess adhesive agent of each polarizing filmformed in Process 2 by lightly wiping and laminating the polarizing filmbetween the retardation film and Polarizing Plate Protective Film Ctreated in Process 1.

Process 4: Adhering the retardation film, the polarizing film andPolarizing Plate Protective Film C laminated in Process 3 by pressingthe films with a tension of 20-30 N/cm² while the films are transportedwith a speed of about 2 m/min.

Process 5: Drying the films adhered in Process 4 in an oven heated at80° C. for 5 minutes to obtain the polarizing plates.

A polyvinyl alcohol film having thickness of 120 μm was uniaxiallystretched at 110° C. with a stretching ratio of 5, which was thenimmersed in an aqueous solution of 0.075 g of iodine, 5 g of potassiumiodide and 100 g of water for 60 seconds. The resulting film was furtherimmersed into an aqueous solution of 6 g of potassium iodide, 7.5 g ofboric acid and 100 g of water at 68° C., followed by washing with waterand drying to obtain a polarizing film.

(Fabrication of Liquid Crystal Display (LCD))

Using the 40 sets of obtained polarizing plates, 40 LCDs were fabricatedby adhering each set of the polarizing plate on the glass panels on bothsurfaces of a liquid crystal cell and providing a LED directillumination backlight unit provided behind the liquid crystal cell.Thus obtained LCDs (VA mode, 37 inch size) were subjected to adurability test under a condition of 6° C., 90% RH for 1000 hours, andthen front contrast of each LCD was measured using EZ-Contrast producedby ELDIM. When the highest contrast value among those of the 40 LCDs wasset to 100, number of LCDs exhibiting a contrast value in the range of90-100 was counted and evaluated according to the following criteria.From the results, the LCDs in which polarizing plates of the presentinvention were employed were found to exhibit uniform contrast valuesresulting in providing uniform LCDs.

A: 39-40 LCDs in 40 LCDs

B: 37-38 LCDs in 40 LCDs

C: 35-36 LCDs in 40 LCDs

D: 33-34 LCDs in 40 LCDs

E: 32 LCDs or less in 40 LCDs

The polarizing plate which gives the evaluation of C or better issuitable for practical use.

The above results were summarized in Table 1. TABLE 1 Free Front Stretchvolume Free contrast temperature Stretch radius volume of *1 Dope *2 *3*4 (° C.) ratio (nm) parameter *5 *6 *7 *8 display Remarks 1 A 105 12 —120 1.3 0.310 2.0 −2 −3 ±3% ±3% C Inv. 2 A 110 15 — 120 1.3 0.305 1.9 −1−2 ±2% ±2% B Inv. 3 A 120 15 — 120 1.3 0.301 1.9 −1 −2 ±2% ±2% B Inv. 4A 125 15 1 120 1.3 0.285 1.4 0 0 less less A Inv. than than ±1% ±1% 5 A125 25 5 120 1.3 0.275 1.2 0 0 less less A Inv. than than ±1% ±1% 6 A130 25 — 120 1.3 0.301 1.9 −1 −1 ±2% ±1% B Inv. 7 A 130 25 3 120 1.30.280 1.7 0 0 less less A Inv. than than ±1% ±1% 8 A 135 25 10  120 1.30.250 1.0 0 0 less less A Inv. than than ±1% ±1% 9 A 140 15 — 120 1.30.295 1.9 −1 −1 ±2% ±1% B Inv. 10 A 145 15 1 120 1.3 0.271 1.5 0 0 lessless A Inv. than than ±1% ±1% 11 A 150 20 — 120 1.3 0.308 1.9 −1 −1 ±2%±1% B Inv. 12 A 150 35 1 120 1.3 0.295 1.8 0 −1 less less A Inv. thanthan ±1% ±1% 13 A 155 45 — 120 1.3 0.310 1.9 −2 −3 ±3% ±3% C Inv. 14 A100 15 — 120 1.3 0.315 2.2 −4 −7 ±5% ±5% E Comp. 15 A 100 10 — 120 1.30.320 2.2 −5 −9 ±7% ±6% E Comp. 16 A 110 10 — 120 1.3 0.312 2.2 −4 −6±5% ±5% E Comp. 17 A 150 10 — 120 1.3 0.311 2.2 −4 −7 ±6% ±5% E Comp. 18A 160 20 — 120 1.3 0.312 2.3 −4 −6 ±5% ±5% E Comp. 19 B 125 25 1 120 1.30.298 1.7 −1 −3 ±2% ±3% B Inv. 20 B 135 25 3 120 1.3 0.300 1.6 −1 −3 ±2%±3% B Inv. 21 B 100 10 — 120 1.3 0.325 2.2 −6 −10 ±6% ±5% E Comp. 22 B160 10 — 120 1.3 0.315 2.3 −5 −9 ±5% ±5% E Comp.*1: Cellulose ester film No.,*2: Treatment temperature (° C.),*3: Atmosphere replacement rate (times/h),*4: Treatment pressure (kPa)*5: Ro change before and after saponification,*6: Rt change before and after saponification,*7: Ro distribution after saponification,*8: Rt distribution after saponificationInv.: Inventive Sample,Comp.: Comparative Sample

From the results shown in Table 1, the retardation film having a freevolume radius and a free volume parameter lying within the ranges of thepresent invention, which was obtained by controlling the heat treatmenttemperature after the drying process, the rate of atmosphere replacementand the pressure in the press treatment, provides a polarizing plate anda LCD exhibiting small changes in Rt and Ro values before and after thesaponification and small fluctuations in Rt and Ro values in theretardation films.

1. A polarizing plate comprising a polarizing film having thereon aretardation film containing a plasticizer and a cellulose ester, whereina free volume radius of the retardation film determined by positronannihilation lifetime spectroscopy is in the range of 0.250-0.310 nm. 2.The polarizing plate of claim 1, wherein a free volume parameter of theretardation film is in the range of 1.0-2.0.
 3. The polarizing plate ofclaim 1, wherein the cellulose ester is an ester of mixed aliphaticcarboxylic acids each having 2-22 carbon atoms.
 4. The polarizing plateof claim 1, wherein Ro and Rt defined by the following formulas satisfythe following conditions: Ro is in the range of 30-300 nm; and Rt is inthe range of 70-400 nm, whereinRo=(nx−ny)×dRt=(((nx+ny)/2)−nz)×d wherein Ro represents an in-plane retardationvalue; Rt represents an out-of-plane retardation value in a thicknessdirection; nx represents an in-plane refractive index in a slow axisdirection; ny represents an in-plane refractive index in a fast axisdirection; nz represents an out-of-plane refractive index in thethickness direction; and d represents a thickness (nm) of theretardation film.
 5. A display comprising a liquid crystal cell, adirect illumination backlight unit and the polarizing plate of claim 1.